Electronics and Communication Projects (ECE)- III

Helical Resonator Notch Filter: (electronic circuit added 7/03)
High Q Notch Filter: National Semiconductor Application Notes first published28-Jun-1996 (app note added 4/02)
High-Q 60-Hertz Notch Filter: This high-Q notch filter is based on the "Twin-T" design. It produces a very deep notch in the response curve at about 59.7 Hz. This is useful to remove 60-Hz hum and noise from audio recordings or live performances. Response is down over -60db at the center point. The LM3900 Norton opamp was chosen since it doesn't require extra components for single-supply operation.... (circuit design added 7/06)
KHN Inverting Input Second Order Notch non-inverting: (electronic design added 6/07
KHN Non-Inverting Input Second Order Notch inverting: (electronic design added 6/07)
LB-5: High Q Notch Filter: National Semiconductor Application Note (app note added 2/06)
Mikhael-Bhattacharyya MB Second Order Notch non-inverting: (electronic design added 6/07)
Notch Filter is DC Accurate: 03/02/95 EDN Design Ideas / (added 7/02)
Notch Filter is Insensitive to Component Tolerances: 03/02/00 EDN-Design Ideas / (added 2/06)
Notch Filter uses Only Lowpass Filters: 04/10/97 EDN Design Ideas / (added 6/06)
Notebook Power Supply has Two Outputs: 03/03/94 EDN-Design Ideas / (added 3/06) The notebook-computer supply in Fig 1 powers the 5V logic and derives an adjustable -24V supply for an LCD's backplane. The design uses only a high-efficiency buck regulator (Si9150) and an NMOS/PMOS, dual-power-FET chip set (Si9943), eliminating the extra parts required when you implement both supplies independently. Because of the low on-resistances of the dual FETs, this circuit can achieve better than 92% efficiency at 7.2V input and full-load output (7.6W)....
RC Notch Filter Twin T: The twin T notch filter can be used block an unwanted frequency or if placed around an op-amp as a bandpass filter. The notch frequency occurs where the capacitive reactance equals the resistance Xc=R and if the values are close, the attenuation can be very high and the notch frequency virtually eliminated. (added 4/02)
Reverse RIAA Equaliser: Test phono preamps for correct equalisation, or convert unused phono inputs. (circuit added 6/07)
Sallen-Key SK Second Order Notch non-inverting: (electronic design added 6/07)
Simple Easy Parametric and Graphic Eq's Plus Peaks and Notches: (circuit / schematic design added 6/06)
Switched-capacitor IC forms notch filter: 09/30/99 EDN-Design Ideas / (added 10/06)
Twin-T Second Order Notch I non-inverting: (electronic design added 6/07)
Twin-T Second Order Notch II non-inverting: (electronic design added 6/07)
Variable notch filter with both high and low pass filters: (schematic / circuit added 2/07)
1 Wire Barometer: (electronic diagram added 6/03)
12-Bit 8-Channel Data Acquisition System Interfaces to IBM PC Serial Port: DN35 Design Notes (Linear Technology) (app note added 1/06)
16-Channel 24-Bit Delta Sigma ADC Provides Small Flexible and Accurate Solutions for Data Acquisition: DN297 Design Notes (Linear Technology) (app note added 6/06)
1-Wire Barometer: circuit requires an additional power source or than that of 1-Wire network. MPX4115 requires about 7 ma of current. This is more than a 1-Wire network can provide without an elaborate circuit to store parasitic power from 1-Wire network for short burst of current for pressure measurements. Two voltage regulators are used to provide both 5.0 and 10.0 voltages from a source of DC power ranging from 12 to 24 volts. (added 2.07)
A 70-W S-Band Amplifier For MMDS and Wireless Data/Internet Applications (12/11/00) : Application Note California Eastern Laboratories Doc #932 (app note added 11/06)
Linkwitz Transform Circuit: The Linkwitz Transform circuit - an equaliser to provide extended bass response (circuit added 6/07)
Low-Sensitivity, Bandpass Filter Design with Tuning Method: National Semiconductor Application Note (app note added 2/06)
Method of Designing Multiple Order All Pole Bandpass Filters by Cascading 2nd Order Sections: AN27A Linear Technology Presents two methods of designing high quality switched capacitor bandpass filters. Both methods are intended to vastly simplify the mathematics involved in filter design by using tabular methods. The text assumed no filter design experience but allows high quality filters to be implemented by techniques not presented before in the literature. The designs are implemented by numerous examples using devices from LTC's SwitchedCapacitor filter family: LTC1060, LTC1061, and LTC1064. Butterworth and Chebyshev bandpass filters are discussed. (app note added 6/06)
Micro-power Band-pass Network: Circuit Ideas for Designers Application Notes Advanced Linear Devices, Inc. (app note added 6/06)
Mikhael-Bhattacharyya MB Second Order Bandpass non-inverting: (electronic design added 6/07)
Multiple Feedback Bandpass Filter sound.au: This is the basis of an expandable equaliser and analyser or vocoder (schematic added 9/02)
Multiple Feedback Bandpass Filter: (electronic circuit added 7/03)
Multiple Feedback MFB Second Order Bandpass I inverting: (electronic design added 6/07)
Multiple Feedback MFB Second Order Bandpass II inverting: (electronic design added 6/07)
Narrow Band Audio Bandpass Filter: (electronic circuit added 7/03)
OA-28: OA-28 Low-Sensitivity, Bandpass Filter Design with Tuning Method: National Semiconductor Application Note (app note added 2/06)
Sallen-Key SK Second Order Bandpass non-inverting: (electronic design added 6/07)
Self Tune Filter: (electronic circuit added 7/03)
Simple Method of Designing Multiple Order All Pole Bandpass Filters by Cascading 2nd Order Sections: AN27A Linear Technology Presents two methods of designing high quality switched capacitor bandpass filters. Both methods are intended to vastly simplify the mathematics involved in filter design by using tabular methods. The text assumed no filter design experience but allows high quality filters to be implemented by techniques not presented before in the literature. The designs are implemented by numerous examples using devices from LTC's SwitchedCapacitor filter family: LTC1060, LTC1061, and LTC1064. Butterworth and Chebyshev bandpass filters are discussed. (app note added 6/06)
Single Op-Amp Bandpass Filter: A bandpass filter passes a range of frequencies while rejecting frequencies outside the upper and lower limits of the passband. The range of frequencies to be passed is called the passband and extends from a point below the center frequency to a point above the center frequency where the output voltage falls about 70%.... (added 2/07)
Tow-Thomas TT Second Order Bandpass inverting: (electronic design added 6/07)
Twin-T Second Order Bandpass inverting: (electronic design added 6/07)
Active 2nd Order Filters: (electronic circuit added 7/03)

Akerberg-Mossberg AM Second Order Highpass inverting: (electronic design added 6/07)

Berka-Herpy BH Second Order Highpass non-inverting: (electronic design added 6/07)
Butterworth Filters: (electronic circuit added 7/03)

Chebyshe Volt Bandpass Filter: (electronic circuit added 7/03)

Chebyshe Volt/Butterworth Filters: (electronic circuit added 7/03)

First Order Highpass I non-inverting: (electronic design
A Collection of Differential to Single-Ended Signal Conditioning Circuits for Use with the LTC2400 a 24-Bit No Latency Δσadc in an SO-8: AN78 Linear Technology This application note describes six low power differential-tosingleended signal conditioning circuits for LTC2400 No Latency ΔΣTM 24-bit ADC. These circuits offer customer a number of choices for conditioning differential input signals as low as 5mV to as high as ±2.5V, as well as operation on a single 5V or ±5V supplies. Each circuit description also covers circuit design and implementation techniques that can help preserve LTC2400's inherently high effective resolution. AN78 concludes with two circuits for digitizing temperature when using an RTD or Type S rmocouple.
A Two Wire Isolated and Powered 10-Bit Data Acquisition System: DN19 Design Notes (Linear Technology) (app note added 1/06)
Accelerometer Schematic: (diagram added 2/07)
Acquisition system is Programmable on the fly: 10/12/95 EDN-Design Ideas / (added 11/05) The programmable data-acquisition system in Fig 1 can take 333k samples/sec using a 3-µsec sampling ADC, IC3. Multiplexer IC1 and programmable gain amplifier (PGA) IC2 provide four truly differential channels and four decade gains of 1, 10, 100, and 1000. These features allow circuit to handle low-signal sensors without additional conditioning circuitry. The circuit does not require an S/H amplifier due to ADC's sampling structure. If you want to handle noisy and high-speed signals, you may need to add an antialiasing filter in front of ADC. The heart of system is a 4x4 register file, IC5, which essentially controls ....
Acquisition Times of the ADN2812: AN-757 Analog Devices Application Notes (app note added 2/06)
Ad-03: Effects of Aperture Time and Jitter in a Sampled Data: National Semiconductor Application Note (app note added 2/06)
ADC to PC interface Transfers data in nibbles : 12/09/99 EDN-Design Ideas / (added 6/06) -The circuit in Figure 1 uses a Centronics printer port to interface an eight-channel, 8-bit ADC to a PC. The circuit cuts cost of addressing and decoder circuitry and saves one expansion slot for interfacing. The design uses three of subport...
Addressable ADC: (electronic diagram added 6/03)
ADXL202 accelerometer to CV output: (diagram added 2/07)
AN-1041: CHANNEL LINK Moving and Shaping Information in Point-To-Point Applications: National Semiconductor Application Note (app note added 2/06)
AN-22: Integrated Circuits for Digital Data Transmission: National Semiconductor Application Note (app note added 2/06)
AN26(A-R) Interfacing the LTC1090/1/2: AN26 Linear Technology A collection of interface applications between various microprocessors/ controllers and LTC1090 family of data acquisition systems. The note is divided into sections specific to each interface. (app note added 2/06)
AN-281: Data Acquisition using Ins8048: National Semiconductor Application Note (app note added 2/06)
AN-282: Fundamentals of Sampled Data Systems: AN-282 Analog Devices Application Notes (app note added 6/06)
AN-383: Embedded Shock and Temperature Recorder: AN-383 Analog Devices Application Notes (app note added 2/06)
AN-578: RMS Calculations for Energy Meter Applications using the ADE7756: AN-578 - Analog Devices Application Notes (app note added 2/06) The document describes the implementation of an rms signal processing algorithm using the ADE7756 and a Microcontroller (PIC16C63) from Microchip.
AN-626: Using the AD7732/AD7734/AD7738/AD7739 Checksum Register: AN-626 - Analog Devices Application Notes (app note added 2/06)
High Input Impedance DC Summing Amplifier: Circuit Ideas for Designers - Application Notes - Advanced Linear Devices, Inc. (app note added 2/06)
High Input Impedance Precision DC Summing Amplifier: Circuit Ideas for Designers - Application Notes - Advanced Linear Devices, Inc. (app note added 3/06)
Low Voltage High Input Impedance Precision DC Summing Amplifier: Circuit Ideas for Designers - Application Notes - Advanced Linear Devices, Inc. (app note added 2/06)
AN-214: Ground Rules for High Speed Circuits: AN-214 - Analog Devices Application Notes (added 2/06) Layout and Wiring Are Critical in Video Converter Circuits.
AN-282: Fundamentals of Sampled Data Systems: AN-282 - Analog Devices Application Notes (added 2/06)
AN-347: Shielding and Guarding: AN-347 - Analog Devices Application Notes (added 2/06) How to Exclude Interference-Type Noise. What to do and Why to do it-A Rational Approach
AN-357: Operational Integrators: AN-357 - Analog Devices Application Notes (added 2/06)
AN-358: Noise and Operational Amplifier Circuits: AN-358 - Analog Devices Application Notes (added 2/06)
AN-584: Using the AD813X Differential Amplifier: AN-584 - Analog Devices Application Notes (added 2/06) The AD813x differs from conventional op amps by the external presence of an additional input and output. The additional input, VOGM, controls the output common mode voltage.
AN-589: Ways to Optimize the Performance of a Difference Amplifier: AN-589 - Analog Devices Application Notes (added 2/06) This Application Note presents several ways to build and optimize the performance of a discrete difference amplifier. It also recommends amplifiers that will make the overall solution cost/performance competitive with monolithic instrument amplifiers.
AN-649: Using the Analog Devices Active Filter Design Tool: AN-649 - Analog Devices Application Notes (added 2/06)
AN-772: A Design and Manufacturing Guide for the Lead Frame Chip Scale Package (LFCSP): AN-772 - Analog Devices Application Notes (added 2/06)
27MHz toy car receiver: (Circuit / schematic design added 6/06)
500mW HF Linear Amplifier: (Circuit / schematic design added 6/06)
500w HF Linear Amplifier: (Circuit / schematic design added 6/06)
Active Antenna for HF-VHF-UHF: (Circuit / schematic design added 6/06)
Composite Amp Provides High Gain and Bandwidth: 04/28/94 EDN-Design Ideas / (Electronic Schematic / circuit added 04/02) The composite circuit in Fig 1 couples the output drive and slew rate of a current-feedback amplifier, IC2, with the low-noise and low-offset characteristics of a voltage-feedback operational amplifier, IC1. The circuit achieves gains as high as 1000, while showing little variation in frequency characteristics with gain. This circuit suits applications requiring high gain and wide dynamic range, such as ultrasound, radar, digital radio, and other high-noise applications....
Singlesideband Demodulator Covers the HF Band: 10/26/00 EDN-Design Ideas / (Circuit added 9/04)
Wideband Opamp Capable of Micropower Operation : National Semiconductor Application Note 24-Oct-2001 (added 1/03)
Wideband Opamp Capable of Micropower Operation : National Semiconductor Application Note 24-Oct-2001 (added 1/03)
Analog Input Circuit Serves Any Microcontroller: 12/20/01 EDN Design Ideas / (added 10/03) The simple ADC in Figure 1 is perfect for getting analog signals into a purely digital microcontroller. Using just five surface-mount parts, you can assemble it for less than 50 cents (1000), which is approximately half cost of a single-chip- ADC approach in same volume. Moreover, this design takes only one pin from microcontroller to operate. .
LED Driver Delivers Constant Luminosity: 06/12/03 EDN Design Ideas / (added 12/04) The circuit in Figure 1 is similar in principle to that of a previous Design Idea (Reference 1) but offers improved, more reproducible performance. The output current is almost constant over an input-voltage range of 1.2 to 1.5V and is insensitive to variations of transistor gain. Transistors Q1 and Q2 form an astable flip-flop....
Network Imitates Thermocouples: 11/08/01 EDN Design Ideas / (added 12/04) Thermocouples find widespread use for temperature measurement in systems. During system design or testing, you must observe the system's response at different temperatures. However, it's inconvenient to heat a thermocouple every time you need to check a system's performance. You can use the simple trick of touching the thermocouple with a hot soldering iron, but this method provides only ... ...
Positive Feedback Yields Fast Amplifier with Precision DC Offset: 04/01/04 EDN Design Ideas / (added 1/05) Some signal-processing applications require a high-speed, low-noise, dc-coupled amplifier that incorporates a precision dc-offset adjustment. Examples include oscilloscopes, in which the offset adjustment typically acts as a "position" control), ADC-input gain blocks, and scanning-ion-beam-microscopy deflection circuitry....
Temperature Sensing with a Programmable Gain Amplifier: Microchip Application Note Published 26-Jun-03 (app note added 2/06)
TV/Radio Antenna Cable galvanic isolator: (electronic circuit added 8/03)
Using the AD7732/AD7734/AD7738/AD7739 Checksum Register: AN-626 - Analog Devices Application Notes (app note added 2/06)
Video Emitter uses Battery Power: 08/30/01 EDN Design Ideas / (added 12/04) The block diagram in Figure 1 shows how to make a cable-free, direct-video system. The system allows users to walk from booth to booth at an exhibition to interview people and to display the interviews in real time on three screens at key locations. You can use the small and simple system each time you need to capture image and sound on the run. ...
Anticipating timer switches before you push the button: 04/03/03 EDN-Design Ideas / (Electronic circuit added 10/03) (Editor's note: This Twilight Zone-worthy circuit will be the subject of an upcoming network sitcom, My Big Fat Anticipating Timer.) It happens to almost everyone that an apparatus or system should have been turned off a moment ago. The device in question could be the car heater, the air conditioner, the lights
Air Flow Detector #1: This simple circuit uses an incandescent lamp to detect airflow. With the filament exposed to air, a constant current source is used to slightly heat the filament. As it is heated, the resistance increases. As air flows over the filament it cools down, thus lowering its resistance. A comparator is used to detect this difference and light an LED. With a few changes, the circuit can be connected to a meter or ADC to provide an estimation on the amount of airflow. (Electronic Schematic / circuit added 4/02)
Airflow Monitor Protects Components: 09/28/95 EDN-Design Ideas / (Electronic Schematic / circuit added 4/02)
Sensing Air Flow with the PIC16C781: Microchip Application Note - Published 30-Dec-02 (added 2/06)
TB044: Sensing Air Flow with the PIC16C781: Microchip Application Note - Published 30-Dec-02 (added 2/06)
Aircraft Receiver: (electronic circuit added 7/03)
AM Receiver for Aircraft Communications: (electronic circuit added 7/03)
AM-Receiver for Aircraft Communication (118.250MHz): (electronic circuit added 4/05)
AM2 circuit: (circuit / schematic design added 6/06)
Amplitude Modulation of the AD9850 Direct Digital Synthesizer: AN-423-Analog Device Application Notes (app note added 6/06)
Am-Receiver for Aircraft Communication (118.250MHz): (electronic circuit added 4/05)
Designing an AM Receiver For Low Power Wireless Systems Using the NEC UPC2768GR IC (7/22/96) : Application Note California Eastern Laboratories Doc #921 (app note added 6/06)
General Purpose RF Amplifier: (electronic circuit added 1/03)
How to Build a 300MHz AM RF Remote Control System: (circuit / schematic design added 6/06)
KD2BD ATV AM Video Modulator: video signal processing circuit that allows adjustment of video gain, video bias, sync and sync level (added 6/06)
Limiting Amplifier Forms AM Modulator: 12/07/95 EDN-Design Ideas / (added 4/02)
Voltage to Current Converter Drives White LEDs: 06/27/02 EDN Design Ideas / (added 12/04) You sometimes need to drive a white LED from one 1.5V battery. Unfortunately, the forward voltage of a white LED is 3 to 4V. So, you would need a dc/dc converter to drive the LED from one battery. Using the simple circuit in Figure 1, you can drive one white LED or two series-connected green LEDs, using only a few components....
Ways to Optimize the Performance of a Difference Amplifier: AN-589 Analog Devices Application Notes (app note added 6/06) This Application Note presents several ways to build and optimize the performance of a discrete difference amplifier. It also recommends amplifiers that will make the overall solution cost/performance competitive with monolithic instrument amplifiers.
Agilent TS-5400 Series II Automotive Electronics Functional Test System: Agilent Application Note (added 6/06)
AN-70-001 Fixed attenuators help minimize impedance mismatches: Application Note MiniCircuits.com (app note added 6/07)
AN-70-001 Fixed attenuators help minimize impedance mismatches: Application Note MiniCircuits.com (app note added 6/07)
Audio-test accessory isolates and matches loads: 3/16/06 EDN Design Ideas / (added 10/06) This low-cost, switchable, dual-impedance transformation circuit comprises a single conventional transformer and two minimum-loss pads.
Fixed attenuators help minimize impedance mismatches: AN-70-001 Application Note MiniCircuits.com (app note added 6/07)
High Input Impedance Precision DC Summing Amplifier: Circuit Ideas for Designers Application Notes Advanced Linear Devices, Inc. (app note added 6/06)
High-impedance voltmeter: An ideal voltmeter has infinite input impedance, meaning that it draws zero current from the circuit under test. This way, there will be no "impact" on the circuit as the voltage is being measured. The more current a voltmeter draws from the circuit under test, the more the measured voltage will "sag" under the loading effect of the meter, like a tire-pressure gauge releasing air out of the tire being measured...(schematic added 6/07)
Measuring Characteristic Impedance of Short Rambus Motherboard Traces and Small-Outline RIMMs: Agilent Application Note (added 6/06)
Variable Amplifier Impedance: idea of being able to vary the output impedance of a power amplifier (added 6/06)
40 Meter Popcorn Superhet Receiver: This schematic is a relatively low-cost CW superhet receiver with a 4.00 MHz Intermediate frequency. re is no AGC or RF gain control, however this receiver has good large signal handling capability. This receiver uses just 6 bipolar transistors and an op amp for reasonable volume into headphones. Much of ideas/design of various stages must ... (added 02/05)
AN-502: Designing a Superheterodyne Receiver using an IF Sampling Diversity Chipset: AN-502 Analog Devices Application Notes (app note added 10/06) The AD6600/AD6620 Chipset Simplifies Receiver Design
HDT Technology Adds Power to CDMA Chip Set: RF Micro Devices Application Note TA0003 (added 02/05)
I.F. Amplifier: The I.F. transformer primary has 18 turns, the secondary winding has 4 turns. The capacitors across the IFT primaries are 82pF. The input/output transformer has 12 turns, tapped at 3 turns from ground. This transformer is wound on a ferrite core. The mosfets are 3SK45's. The diodes in the product detector are 1N34's. I use a six pole SSB filter from a scrap CB. The centre frequency is 7.8MHz. The -6db bandwidth is about 2.5KHz. (added 02/05)
Low Distortion IF Amplifier/ ADC Driver with Digitally Controlled Gain: Linear Technology LT5524 (app note added 02/05)
Tunable IF with TDA7000: The main motive of the mods was not that the circuit didn't work right, but were several tries to add some kind of frequency indicator to the receiver. The left RCA plug and associated components are witnesses to the last version, adding a FET buffer amplifier and taking signal from the oscillator coil. (added 02/05)
UltraLow Distortion IF Amplifier/ ADC Driver with Digitally Controlled Gain: Linear Technology LT5514 (app note added 02/05)
4 MHz Amplitude Modulated RF Source : A while back I needed an amplitude modulated signal source at 4 MHz. This circuit was literally thrown together with parts laying on the bench. I built it dead bug style on a piece of copper clad board. It should work with little or no modification, other than the selection of the crystal, at other frequencies. At lower frequencies you might have to increase the capacitor values to get it to oscillate, and at higher frequencies, you might have to reduce the capacitor values a little...(circuit added 6/07)
40 Meter Direct Conversion Receiver: (electronic (schematic / circuit added 11/06)
AM Broadcast Band Regenerative Receiver: (circuit / schematic design added 6/06)
Am Loop Antennas by Bruce Carter: (circuit added 9/04)
AM Radio PreAmplifier: (circuit added 9/04)
AM Receiver for Aircraft Communications: (electronic circuit added 4/05)
AM Receiver: (schematic added 9/02)
AM Transmitter #2: (design added 8/03)
AM/FM/SW Active Antenna: This circuit shows an active antenna that can be used for AM, FM, and shortwave SW. On the shortwave band this active antenna is comparable to a20 to30 foot wire antenna. This circuit uses receivers that use untuned wire antennas, such as inexpensive units and car radios. L1 can be selected for the application (added 4/02)

A Compact Algorithm using the ADXL202 Duty Cycle Output: AN-603 - Analog Devices Application Notes (added 2/06)
Algorithm Extracts Cube Root : 1/15/98 EDN Design Ideas / (Schematic / circuit added 10/05)
Algorithm Extracts Roots of Decimal Numbers: 04/29/99 EDN-Design Ideas / (Schematic / circuit added 10/05) "Algorithm extracts cube root" (EDN, Jan 15, 1998, pg 100) covers only the one-third power (cube root). In contrast, the C routine in Listing 1 calculates the Kth root (X1/K) of positive decimal numbers X. Both K and X can vary widely. You type in X, K, and an estimate of the root; the routine then calls the calcRoot function in the software program. Upon calculating the root, the routine prints on screen the number of iterations performed and the root result X1/K. The routine raises this result to the Kth power and displays the result so you can make a comparison with the original X. The algorithm applies a Newton-Raphson approach to the equation Y=X1/K. If you differentiate the equation and express it in recursive form, you obtain....
Algorithm Yields Precise Bessel Function: 11/09/95 EDN-Design Ideas / (Schematic / circuit added 10/05)
AN-603: A Compact Algorithm using the ADXL202 Duty Cycle Output: AN-603 - Analog Devices Application Notes (added 2/06)
White LED Driver provides 64 step logarithmic dimming: 06/10/04 EDN Design Ideas / (added 1/05) The circuit in this Design Idea is designed for portable-power applications that require white LEDs with adjustable, logarithmic dimming levels. The circuit drives as many as four white LEDs from a 3.3V source.
AN752: AN752 CRC Algorithm for Mcrf45x Read/Write Device: Microchip Application Note - Published 15-Mar-01 (added 2/06)
Composite Amplifier Improves Noise : 08/04/94 EDN-Design Ideas / (Electronic Schematic / circuit added 4/02) Amplifying low-signal levels for signal processing often stretches a single op amp's abilities. A composite design can improve the input noise for detecting extremely small signals and can enhance output-drive ability. Both the op amp's noise terms and the thermal noise of the components limit the minimum noise in an op-amp-based design. Furthermore, amplifier noise figures are not at their minimum for low-impedance sources such as 50 Ohm. Using a transformer is a common technique to achieve matched input impedance for maximum power transfer. Fig 1 shows one example, which follows the transformer with a composite amplifier to achieve a lower input noise figure...
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Low Noise Microphone PreAmplifier: (Electronic circuit added 7/03)

Low Noise Amplifier for Phase Noise Measurements: features less input noise than a 50 ohmresistor. (Electronic circuit added 7/03)
A Versatile Hybrid Synthesizer for UHF and Microwave Projects: Controlled by PC parallel port, this hybrid DDS/PLL synsizer delivers full-octave coverage between 1000 and 2000 MHz with sub-1 Hz resolution and commercial-quality phase-noise performance. (added 6/06)
Microwaves and RF Magazine Cover Feature: CEL and eRide Team to Provide Embedded GPS Solution : Application Note California Eastern Laboratories Doc #913 (app note added 6/06)
Ultrasonic radar: This is a very interesting project with many practical applications in security and alarm systems for homes, shops and cars. It consists of a set of ultrasonic receiver and transmitter which operate at the same frequency. When something moves in the area covered by the circuit the circuit’s... (electronic design added 6/07)
Unusual Radar Detector : (electronic (schematic / circuit added 2/05)
Yaesu FT 736R Doppler Compensation: (electronic (schematic / circuit added 2/05)
1 In/4 Out Audiodistribution Amplifier : (diagram added 6/03)
2 Wire Remote Microphone Amplifier : (diagram added 6/03)
40 MHz Programmable Video Op Amp: National Semiconductor Application Note (app note added 2/06)
741 Op-Amp Tutorial: (electronic design / schematic added 2/06)
A Design and Manufacturing Guide for the Lead Frame Chip Scale Package (LFCSP): AN-772 Analog Devices Application Notes (app note added 2/06)
A Simplified Test Set for Op Amp Characterization: National Semiconductor Application Note (app note added 2/06)
AB-3: Digital Nulling of Precision Op Amps: AB-3 Analog Devices Application Notes (app note added 6/06)
Amplifier Requires No DC Bias: 03/16/00 EDN-Design Ideas / (added 11/05) Intrinsically capacitive transducers and or high-impedance signal sources usually require ac coupling and a buffer amplifier to condition signal for furr processing. Buffers take many forms, but most of m compromise signal quality through use of external resistors that provide a dc path for input bias current. Recent improvements in op-amp technology allow ac-coupled inputs without need for bias resistors. The new op amps have inputs that operate within supply-voltage span. Some are CMOS, but many use complementary bipolar transistors. For latter, each input connects....
AN-1245: Unlimited Capacitive Load Drive Op Amp Takes Guess Work Out of Design: National Semiconductor Application Note (app note added 2/06)
100W Guitar Amplifier: (circuit / schematic design added 2/07)
12 Watt Valve Guitar Amp: (electronic diagram added 2/07)
220 Watt Power Amplifier: This is a building plan for an audio Amplifier with2 x220-Watt output power. Text is in Finnish. (added 3/06)
2304 and 3456 MHz Power Amplifiers: (electronic circuit added 4/05)
60 Watt into 8 Ohms Power Amplifier: A simple amp to build, uses commonly available parts and is stable and reliable (added 6/06)
AN-60-033 Enhanced Linearity in the HELA-10 Power Amplifier: Application Note MiniCircuits.com (app note added 6/06)
Design of Power Amplifier Using the UPG2118K (7/20/04) : Application Note California Eastern Laboratories Doc #957 (app note added 6/06)
Enhanced Linearity in the HELA-10 Power Amplifier AN-60-033: Application Note MiniCircuits.com (app note added 6/06)
100kHz to1GHz RF Power Detector: Linear Technology LTC5507) (app note added 02/05)
500W, Class E 27.12 MHz Amplifier Using A Single Plastic MOSFET: Application Note Microsemi-formerly Advanced Power Technology APT9903 ( app note added 2/07)
A 50 Mhz, 250w Amplifier Using Push-Pull Arf448a/B: Application Note Microsemi-formerly Advanced Power Technology APT9702A ( app note added 2/07)
A Simple Method to Reduce DC Power Consumption in CDMA RF Power Amplifiers Through the LMV225 and an Efficient Switcher: National Semiconductor Application Note (app note added 6/06)
Controlling TDMA Timeslot Power Levels using the Esg-D Series, RF Signal Generators: Aligent App Note (added 2/06)
General Purpose RF Amplifier: (circuit / schematic design added 6/06)
Generic VHF Power Amplifier: (electronic circuit added 7/03)
Behind the Switch Symbol: AN-355 - Analog Devices Application Notes (app note added 2/06) Use CMOS Analog Switches More Effectively When You Consider Them as Circuits
Mobile Solutions (Mp3 Cell Phone Pda Pmp): Pericom Semiconductor Application Brief # 046 ((app note added 02/05)
The Alexander Current-Feedback Audio Power Amplifier: AN-211 - Analog Devices Application Notes (app note added 2/06)
Anemometer Circuit: (schematic / circuit added 11/06)
Low-Cost Anemometer Fights Dust: App Note 844: Maxim IC (Circuit / schematic design added 6/06)
Self Heated Transistor Digitizes AirfLow: 03/14/96 EDN-Design Ideas / (Electronic Schematic / circuit added 4/02)
6x6 Antenna Loop: (added 8/03)

Active Antenna for HF-VHF-UHF: (Circuit added 9/04)

AM Loop Antennas: (added 1/03)

Antenna Extension Provides Open Door Policy: 02/16/98 EDN-Design Ideas / (Electronic Schematic / circuit added 4/02)

ANTENNProjects: (circuit added 7/02)

Long Loopstick AM Radio Antenna: Wound on a3-foot length of PVC pipe, the long Loopstick antenna was an experiment to try to improve AM radio reception without using a long wire or ground. It works fairly well and greatly improved reception of a weak station130 miles away. A longer rod antenna will probably work better if space allows. The number of turns of wire needed for the Loopstick can be worked out from the single layer, air core inductance formula: (Electronic Schematic / circuit added 4/02)

Q Multiplying Loop Antenna: (added 9/02)

Tesla Power Receiver: (circuit added 7/02)

Yagi Uda Antenna : (circuit added 7/02)
Astable Multivibrator 1: (Electronic Schematic / circuit added 4/02)
Flip Flop Flashers Buzzers Etc.: (Electronic circuit added 7/03)
Add Programmable Gain, Attenuation: AN-254 Analog Devices Application Notes (app note added 6/06) Simple CMOS Multiplying DAC Circuit Provides Digital Control of Gain and Attenuation of Analog Signal
AN-70-004 Digital Step Attenuators offer Precision and Linearity: Application Note MiniCircuits.com (app note added 6/06)
Digital Stereo Potentiometer: in PDF format, text in Finnish (added 4/02)
Precision Attenuator with Digital Control: (electronic Circuit / Schematic added 10/04)
Precision Divide by Two Analog Attenuator Needs No External Components: 03/17/05 EDN Design Ideas / (added 11/05) Many modern A/D converters offer only a 5V input range, and using these converters with a 65V or larger input signal gives the designer a problem: how to discard half of a good analog signal without introducing errors and distortion. To solve the problem, you can use an attenuator comprising two operational amplifiers and two resistors (Figure 1).
30 Ddm to +30 Ddm Audio Level Meter: circuit with balanced input and adjustable gain to drive needle type VU meter, uses special amplifier module from Op-Amp Labs (added 4/02)
Amplified Ear: (circuit added 9/04)
Arc welder sound simulator: (diagram added 2/07)
Audio Detector Circuit: (diagram added 2/07)
Audio graphic equaliser: (diagram added 2/07)

Audio Line Isolator #1: (electronic circuit added 1/03)
Audio Line Isolator #2: (electronic schematic added 8/02)
Audio Transformer #2: notes on using audio transformers for balanced signal interfacing (added 4/02)
Bluetooth Headset: Intersil Application Block Diagram (app note added 6/06)
AN-348: Avoiding Passive-Component Pitfalls: AN-348 Analog Devices Application Notes (app note added 2/06) The Wrong Passive Component Can Derail Even Best Op Amp or Data Converter. Here Are Some Basic Traps to Watch For.
AN-581: Biasing and Decoupling Op Amps in Single Supply Applications: AN-581 Analog Devices Application Notes (app note added 2/06)
AN-60-034 Transient Protection of Darlington gain block Amplifiers: Application Note MiniCircuits.com (app note added 6/07)
AN-683: Strain Gage Measurement using an AC Excitation: AN-683 Analog Devices Application Notes (app note added 2/06)
Applications for a Switched-Capacitor Instrumentation Building Block: AN3 Linear Technology This application note describes a wide range of useful applications for LTC1043 dual precision instrumentation switched capacitor building block. Some of applications described are ultra high performance instrumentation amplifier, lock-in amplifier, wide range digitally controlled variable gain amplifier, relative humidity sensor signal conditioner, LVDT signal conditioner, charge pump F/V and V/F converters, 12-bit A/D converter and more. (app note added 6/06)
ADN2891 Evaluation Board: AN-762 Analog Devices Application Notes (app note added 2/06) This application note describes ADN2891 evaluation board.
100 Watt Guitar Amplifier Mk II: (schematic added 9/02)

AN-762: ADN2891 Evaluation Board: AN-762 Analog Devices Application Notes (app note added 2/06) This application note describes ADN2891 evaluation board.
Limiting Amplifier is Digitally Programmable: 06/04/98 EDN-Design Ideas / (added 11/05) Amplitude limiters are necessary in many systems, such as radar and FM receivers, for which the system cannot allow the amplitude of the signal to exceed the given positive, negative, or both limits. In the circuit in Figure 1, amplifier IC4B's maximum output is digitally programmable over ±2 to ±10V in 2n steps, where n is the number of bits of the DAC. IC1, a precision 10V reference, provides a full-scale reference current, IREF=VREF/R1=2 mA, to IC2, a multiplying DAC. IC3's output voltage, VL, is the sum of the product of the digital word and unipolar...

Aviation Band Receiver: (circuit added 9/04)
12 Volt Alarm Power Supply: (circuit / schematic design added 6/06)
4 Digit Keypad: (diagram added 6/03)
5 Zone alarm circuit MIT: (schematic added 2/07)
5 Zone Alarm Circuit: (electronic schematic added 8/02)
5 Zone Alarm System: (electronic design added 6/07)
5 Zone Alarm: Each zone uses a normally closed contact. se can be micro switches or standard alarm contacts (usually reed switches). Zone 1 is a timed zone which must be used as entry and exit point of building. Zones 2 5 are immediate zones, which will trigger alarm with no delay. Some RF immunity is provided for long wiring runs by input capacitors, C1-C5. C7 and R14 also form a transient suppresser. key switch acts as Set/Unset and Reset switch. For good security this should be .... (added 09/05)
A CMOS Single Zone Intruder Alarm: This circuit features automatic Exit and Entry delays - timed bell cut-off - and system reset. It has provision for normally-open and normally-closed switches - and will suit all of the usual input…(added 05/07)
A Simple Electronic Buzzer: This very simple circuit just uses a couple of resistors, a capacitor and easily available 555 timer IC. The 555 is setup as an astable multivibrator operating at a frequency of about 1kHz that produces a shrill noise when switched on. The frequency can be changed by varying 10K resistor. (added 10/06)
A Transistor Based - Single Zone Alarm: This circuit features automatic Exit and Entry delays - timed bell cut-off - and system reset. It has provision for normally-open and normally-closed switches - and will suit all of the usual input...(added 05/07)
Active IR Motion Detector: (diagram added 6/03)
Alarm Control Keypad: (circuit / schematic design added 6/06)
Alarm PSU: (circuit / schematic design added 6/06)
Alarm System: (design added 8/03)
Alarm Touched Triggered: (electronic Circuit diagram added 03/03)
Almost Ultrasonic Motion Sensor: (diagram added 6/03)
An SCR Based Burglar Alarm: (electronic design added 6/07)
Anit Theft Motorcycle Alarm: (schematic added 9/02)
Anti-Theft Alarm for Bikes: (circuit / schematic design added 6/06)
Anti-Theft Security for Car Audios: (electronic Circuit / Schematic added 10/04)
Automatic Intruder Alarm: (electronic design added 6/07)
Automatic Intruder Alarm: (electronic design added 6/07)
Automatic Intruder Alarm: This is a simple single-zone burglar alarm circuit. Its features include automatic Exit and Entry delays and a timed Bell/Siren Cut-Off. It's designed to be used with the usual types of...(added 05/07)
Automatic Night Lamp with Morning Alarm: (electronic Circuit / Schematic added 10/04)
RIAA Equalized Stereo Phono Preamp: (circuit / schematic design added 6/06)
105 W 6 Channel Surround Sound: This reference design allows customers with limited knowledge of digital audio amplifiers to quickly build solutions, which meet Dolby, EMI and FTC standards, reducing the time-to-market for new consumer audio products. This 6 channel reference design, based on the TDA8925ST and TDA8926J power stages, is available with an output power of 5x15 W + 1x30 W. (circuit design added 3/05)
Surround Processor: Simple Surround Processor. This is built with only conventional parts, and digital delay block, too. So it is very easy to build. (Circuit / schematic design added 6/06)
A Weighting Filter for Audio Measurements: (Circuit / schematic design added 6/06)
Two Tone Audio Oscillator (use for SSB Tests): (added 7/02)
Two Tone Train Horn: (added 10/02)
Audio Level Control Device: compressor circuit based on LED and photodiode / (Electronic circuit added 7/03)

Digital Automatic Gain Control (Agc): (electronic circuit added 7/03)
OA-16: OA-16 Wideband AGC Amplifier as a Differential Amplifier: National Semiconductor Application Note (app note added 6/06)
Wideband AGC Amplifier as a Differential Amplifier: National Semiconductor Application Note 10-Apr-2000 (app note added 4/02)
Wideband AGC has 60 Db Dynamic Input Range: 10/10/96 EDN-Design Ideas / (added 4/02)
30 Ddm to +30 Ddm Audio Level Meter: circuit with balanced input and adjustable gain to drive needle type VU meter, uses special amplifier module from Op-Amp Labs (Circuit / schematic design added 6/06)
Audio Level Indicator: Audio Amplifier output relay delay (Circuit / schematic design added 6/06)
Audio Level Meter: (added 6/03)
Better Volume Control: how to create a log pot that is better than the "real" thing (Electronic Schematic / circuit added 4/02)
Digital Delay Unit for Surround Sound: (added 9/02)
Generating Tone using Pdo: Toshiba 870X Series Application Note (added 2/06)
Guitar Control: CaStand-alone, 9V battery powered unit . Three-level input selector, three-band tone control (circuit design added 3/05)
160 Baud ALDL Hardware Interface: This interface allows the vehicle's ALDL data stream to be displayed in real time on a PC using simple software. The hardware is designed to be able to be constructed by the average hobbyist who has a temperature controlled soldering iron and basic skills in constructing simple electronics. It uses a minimum of (readily available) components consistent with good electronics design. (Electronic circuit added 4/05)
6A door lock motor driver for automotive: AN456, put at low level the enable of the L9937, confirming the hardware switch-off of the motor ; in this condition an output of the half bridge is in... (app note added 6/06)
A solid state blinker for automotive applications: AN454 that limits the output current slew rate (di / dt) during the switching edges.... (Circuit / schematic design added 6/06)
AN10 Automotive Relay Drivers using the ZVN4206AV: Protection Free Interfacing with Avalanche Rated MOSFETs: Zetec Semiconductors - Applications Notes - An alternative solution is provided to the usual large package Darlington effected relay driver. The ZVN4206AV has been designed, processed and rated to withstand significant energy within the breakdown region. This allows the part to absorb back-emf and transient energy, thereby allowing lower component count circuits. (added 2/06)
AN-454: Automotive Multiplex Wiring: National Semiconductor - Application Note (app note added 2/06)
Automatic Dual Output Display: (Electronic Circuit / Schematic added 10/04)
Automotive protection with the rboxx series: AN555 See 4.1 : " Protection standards in automotive applications " for more details.... (app note added 6/06)
BMW R Series Motorcycle Regulator Schematic: (added 8/03)