3 Band Equalizer: (schematic / circuit design added 9/02)
3 Level Audio Power Indicator: Battery-operated Three LED display that connect it to loudspeaker output (added 6/06)
3 Tone Gong: Suitable for use as a door bell (added 6/06)
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 6/06)
300 Watt Subwoofer Power Amplifier: (electronic circuit added 7/03)
Active Subwoofer and Controller: (electronic circuit added 7/03)
AN543: Tone Generation: Microchip Application Note Published 26-Aug-97 (app note added 2/06)
Audio Graphic Equalizer: simple 7 band equalizer (added 4/02)
Audio Level Indicator #2: (circuit added 9/04)
Audio Level Indicator: Audio Amplifier output relay delay (added 6/06)
Audio level meter (VU Meter): This circuit uses just one IC and a very few number of external components. It displays audio level in terms of 10 LEDs. The input voltage can vary from 12V to 20V, but suggested voltage is 12V. The LM3915 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs providing a logarithmic 3 dB/step analog display. LED current drive is regulated and programmable, eliminating need for current limiting resistors. The IC contains an adjustable voltage reference and an accurate ten-step voltage divider. The high-impedance input buffer accepts signals down to ground and up to within 1.5V of positive supply. Furr, it needs no protection against inputs of ±35V. The input buffer drives 10 individual comparators referenced to precision divider. Accuracy is typically better than 1 dB. (added 9/06)
Audio Level Meter: (diagram added 6/03)
Audio Tone Control: (circuit added 7/02)
Automatic Loudness Control: Simple add-on module Switchable "Control-flat" option (added 3/05)
Door Phone Intercom: (schematic / circuit design added 9/02)
Head Set Intercom : (diagram added 6/03)
IFB Intercom : (diagram added 6/03)
Intercom Schematic: (electronic circuit added 4/05)
Low Power Op Amp Audio Amp (Intercom): (circuit / schematic design added 6/06)
Old phones as an intercom (circuitsdb): From: mwandel@bnr.ca (Markus Wandel) I have recently thought about this and come up with a kludgy but workable scheme. Talking over the phones is easy. You put DC current through the phone and.... (added 2/07)
2 Line Output Combiner: Convert consumer equipment stereo signal to mono or combine audio signal from two different equipments to1-input (added 4/02)
Audio Signal Source: Electronic circuit design (added 02/05)
FET Audio Mixer: (circuit added 7/02)
Line Mixer #2: mix two line level sources to one-signal, includes separate volume controls for both signals, passive circuit (added 4/02)
Portable Mixer: High-quality modular design 9V
Stereo Mixer : Can mix four separate audio inputs to mono or stereo output signal (added 4/02)
Two Line Output Combiner: Convert consumer equipment stereo signal to mono or combine audio signal from two different equipments to1-input (added 4/02)
2W Amplifier: Amplifier operates in
20w Amplifier: (electronic circuit added 4/05)
20 Watt GaAs-FET Power on 2.3 GHz: (diagram added 6/03)
2 Watt Amplifier #1: (circuit added 9/04)
18 Watt Audio Amplifier: High Quality very simple unit. No need for a Preamplifier (added 9/04)
100 Watt Guitar Amplifier #2: (schematic / circuit design added 9/02)
1 Watt 2.3 GHz RF Amplifier using a MRF2001: (diagram added 6/03)
Audio PreAmplifier #1: (electronic circuit added 9/03)
Audio PreAmplifier #2: (schematic / circuit added 10/02)
Dynamic Microphone Preamp : Notice how the transistor bias current flows through the microphone. A similar circuit can be used with an 8 ohm speaker but in that case you would put it in place of the emitter resistor. (added 2/05)
FM Band PreAmplifier: (electronic circuit added 7/03)
AN-147: Low Cost IC Stereo Receiver: National Semiconductor Application Note (app note added 2/06)
AN-543 - Stereo FM Transmitter (DSP, 26,085 bytes): AN-543-StereoFMTransmitter-Analog Device Application Notes (app note added 10/06)
JT-MB D Passive Stereo Matrix for M S MIC Technique: (circuit / schematic design added 6/06)
Ms Stereo Microphone: (circuit / schematic design added 6/06)
Low Cost 1000 Watt 300 Volt RF Power Amplifier for 27.12MHz: Application Note Microsemi-formerly Advanced Power Technology APT9701 ( app note added 2/07)
Operating precautions for RF Amplifiers AN-60-008: Application Note MiniCircuits.com (app note added 6/06)
Simple and Inexpensive High-Efficiency Power Amplifier Using New Apt MOSFETs: Application Note Microsemi-formerly Advanced Power Technology APT9403 ( app note added 2/07)
+/-2.5V Current-to-Voltage Converters: Circuit Ideas for Designers - Application Notes - Advanced Linear Devices, Inc. (app note added 6/06)
AN-1244: Photo-Diode Current-To-Voltage Converters: National Semiconductor - Application Note (app note added 6/06)
AN-772: A Design and Manufacturing Guide for the Lead Frame Chip Scale Package (LFCSP): AN-772 - Analog Devices Application Notes (app note added 2/06)
1Variable Regulated Power Supply: (circuit / schematic design added 6/06)
A Digitally Programmable Gain and Attenuation Amplifier Design: AN-137 Analog Devices App Notes (app note added 2/06)
AB-111: Single-Supply Wien Bridge Oscillator: AB-111 Analog Devices Application Notes (app note added 2/06) Wien Bridge Oscillators require only one op amp, important in battery-operation. This circuit operates from a single 9V battery.
Accurately Testing Op Amp Settling Times: AN-256 Analog Devices Application Notes (app note added 2/06)
AN-106: A Collection of Amp Applications: AN-106 Analog Devices App Notes (app note added 2/06) Examines Some of Numerous and Widely Used Applications of Operational Amplifier
48 Input×16 Output Crosspoint IC Eliminates the Need for Multiplexer Amps: 02/20/03 EDN-Design Ideas / (Electronic circuit design added 02/05) Crosspoint switches are ideal for use in video-security systems, which accept multiple camera inputs while providing playback and multiple loop-through to multiple monitors. To provide video loop-through or monitor outputs, these systems often require additional multiplexer amplifiers that can drive standard video loads...
LH0032 Video Amplifier: (Circuit / schematic design added 6/06)
LM359N Video Amplifier: (Circuit / schematic design added 6/06)
NTSC-to-VGA Scan Converter: This is a scan converter for NTSC signal from TV, VCR, LD or DVD to VGA conversion. Your VGA monitor will able to be used for video monitor. (Schematic / circuit added 10/05)
Video Amplifier: This is a Video amplifier that has been constructed by a single special IC LH0024. (Electronic Circuit diagram added 03/03)
Video Inverter: This is a simple one-transistor circuit to invert the whole video signal, including sync pulses. (Electronic Schematic / circuit added 4/02)
12 Bit ADC Upgrades µC's Internal 8 Bit ADC: Maxim Application Notes / 119 / Mar-03 (app note added 6/06)
12-Bit 3msps Sar ADC Solves Pipeline Problems: DN192 Design Notes (Linear Technology) (app note added 1/06)
16-Bit 333ksps ADC Achieves 90db Sinad,100db Thd and No Missing Codes: DN177 Design Notes (Linear Technology) (app note added 1/06)
16mw Serial/Parallel 14-Bit ADC Samples at 200ksps: DN180 Design Notes (Linear Technology) (app note added 1/06)
4 Channel 8 Bit Analog-to-Digital Converter for PC: (circuit added 7/02)
A 3-Phase Power Meter Based on the ADE7752: AN-641 Analog Devices Application Notes (app note added 2/06)
A Geophone/Hydrophone Acquisition Reference Design: AN-566 Analog Devices Application Notes (app note added 2/06) The AD1555/AD1556 24-Bit Sigma-Delta ADC Chipset Provides for Direct Acquisition of High Dynamic Range Sensors.
A Low Cost Watt-Hour Energy Meter Based on the ADE7757: AN-679 Analog Devices Application Notes (app note added 2/06)
Crystal Radio Circuits : (Schematic / circuit added 10/05)
LED Decibel Meter : (Schematic / circuit added 10/05)
Simple 3 Transistor Audio Amp (50 Milliwatt): (Schematic / circuit added 10/05)
Adding Additional Input Channels to the AD7773 & AD7775: AN-210 - Analog Devices Application Notes (app note added 2/06)
An Unbalanced Mute Circuit for Audio Mixing Channels: AN-127 - Analog Devices Application Notes (app note added 2/06)
AN-248: ADG201A/ADG202A and ADG221/ADG222 Performance with Reduced Power Supplies (pdf, 170,252 bytes): AN-248 - Analog Devices Application Notes (added 2/06)
AN-349: Keys to Longer Life for CMOS (pdf, 91,236 bytes): AN-349 - Analog Devices Application Notes (app note added 2/06) Here's How CMOS Can be Protected Against Abuse
AN-686: Implementing an I2C® Reset (pdf, 45,554 bytes): AN-686 - Analog Devices Application Notes (app note added 2/06)
Analog Switch Expands I 2 C Interface: 11/22/01 EDN Design Ideas / (added 12/04) Perhaps the most effective way to gain board space and increase component density is to minimize wiring on the board. A widely used architecture that allows such miniaturization is the I2C bus. Comprising only a bidirectional data line, SDA, and a clock line, SCL, this bus requires no chip selects or other additional connections. ...
Applying IC Sample and Hold Amplifiers: AN-270 - Analog Devices Application Notes (app note added 2/06)
16 Stage BiDirectional LED Sequencer: (circuit added 7/02)
18 Stage LED Sequencer: (circuit / schematic design added 6/06)
2 Transistor 2 LED Flasher: (circuit / schematic design added 6/06)
2 Transistor LED Flasher #1: (circuit added 7/02)
2 Transistor LED Flasher #2: (electronic design added 9/02)
2 Wire Lamp Flasher: Ideal to operate3 to24
220 Volts Flashing Lamps: Especially designed for Christmas tree lamps to replace old rmally-activated switches (added 9/04))
2-wire Lamp Flasher: This circuit has been designed to provide that continuous light lamps already wired into a circuit, become flashing. Simply insert circuit between existing lamp and negative supply. Especially suited for car or panel pilot lights, this device can drive lamps up to 10W.... (design added 11/06)
3rd Brake Light Pulser: (electronic diagram added 6/03)
3 Xenon flashing circuits found in flash for disposable cameras: (electronic schematic
Bandpass Filter: This circuit is taken from the Progressive Communications Receiver in most of the recent ARRL Handbooks. Values for the 40 meter band are shown. (Electronic circuit design added 02/05)
Band-pass filters: (Electronic circuit design added 02/05)
Components of a simple bandpass filter: (Electronic circuit design added 02/05)
Notch Filter Is DC Accurate: 03/02/95 EDN Design Ideas / (circuit added 7/02) Most active filters exhibit noise, distortion, gain error, and dc offset. However, a filter topology that separates the dc and ac paths can eliminate the last two of these unwanted behaviors (Fig 1a). The dc path in this circuit has no op amps and, therefore, no dc offset. The dc path does not have a dc gain error other than -6 dB of attenuation that the R1/R2 divider causes. (This attenuation is absent if you omit the R2 termination.) The ac path consists of C1 and a synthetic inductor comprising two wideband transconductance amplifiers and associated components. The result is an active circuit that emulates the passive filter of Fig 1b...
.
Wideband Filter uses image Parameters: 10/26/00 EDN-Design Ideas / (added 05/03) / PDF contains multiple circuits - scroll to find this circuit
AN-D9: TN06 Series: Battery Back-Up Utilizes Low Threshold: Supertex Semiconductors (app note added 2/06)
Battery Backup Converter uses One NiCd Cell: 02/03/97 EDN Design Ideas / (Circuit / schematic design added 6/06) Notebook computers and other portable equipment often use a backup battery to retain memory contents during replacement of the main battery. Such "bridge batteries" usually consist of five or six series-connected NiCd coin cells. They're expected to keep the system alive for approximately 5 minutes—plenty of time to swap batteries. The circuit in Figure 1 reduces size, weight, and cost by using one NiCd cell instead of five or six. A Saft VB4E 40-mAhr NiCd coin cell has enough capacity to keep a typical notebook computer in suspend mode for approximately 10 minutes. All components (excluding the coin cell) consume less than 1/2 in.2 of pc-board area, and the cost savings from fewer cells help pay for the added circuitry.....
Buck Converter Handles Battery Backup System: 04/24/03 EDN Design Ideas / (added 12/04) A synchronous buck converter is inherently bidirectional. That is, it transfers energy from input to output as a buck regulator when the output voltage is low, but, when the output voltage is high, the converter acts as a boost regulator, transferring power from output to input. This Design Idea shows how to use this bidirectional energy transfer to automatically recharge a battery when the mai......
Memory Supply Includes Battery Backup: 02/03/97 EDN-Design Ideas / (Circuit / schematic design added 6/06)
Microcontroller Provides SrAM Battery Backup: 06/26/03 EDN Design Ideas / (added 12/04) To maintain content in the event of power loss, many designs that include SRAM require a dedicated device that can automatically switch from a standard power supply to battery operation. Microcontrollers seldom find use in power-switching applications. Because microcontrollers typically operate from the primary power supply, they stop execution if that supply drops, thereby making it impossible......
TN06 Series: Supertex Semiconductors (app note added 2/06)
Amplified Zener: A 13 volt Zener diode will work well for charging a 12 volt battery on Standby use. Or use a 14 volt zener a diode for a Standard 14.6 volt charge…. (circuit / schematic design added 10/06)
Battery Charger: Current and Voltage Regulated for Sealed Lead Acid types (electronic circuit added 10/06
Battery Discharge Monitor: (schematic / circuit added 10/02)
Battery Equal Charge Indicator: (circuit / schematic design added 6/06)
Broken Charger-Connection Alert: Detects if a device is not properly connected to its supply. Suitable for battery chargers, portable appliance supplies etc. (added 3/050
Charge Monitor for 12 Volt Rechargeable Lead Acid Battery: (electronic Circuit / Schematic added 10/04)
Motor Accu Lader: Electronic circuit (added 9/04)
Muscle power drives battery-free electronics: 11/21/05 EDN Design Ideas / (added 10/06) Your sweat and a super-cap replace the battery.
Picref-5: Smbus Level-3 Battery Charger/Selector Reference Design Based on the PIC16C73a: Microchip Application Note Published 11-May-98 (app note added 2/06)
Salt Water Battery: (electronic circuit added 10/05)
Solar Cell Battery Charger: (electronic circuit added 10/06)
Step Up supply charges battery while serving load : The circuit in Fig 1 supports portable applications in which a microprocessor controls battery charging. Step-up switching regulator IC1 boosts VIN (5V) to supply a combination of charging and load current. (Note that the 5V source must have short-circuit protection.) IC2 is a high-side current-sense amplifier that monitors charging current. Commands from the processor are CHARGE ON /OFF and FAST/TRICKLE CHARGE 06/08/95 EDN-Design Ideas / (added 11/05)
The Amplified Zener: A 13 volt Zener diode will work well for charging a 12 volt battery on Standby use. Or use a 14 volt zener a diode for a Standard 14.6 volt charge…. (circuit / schematic design added 10/06)
Zap Adapter: "Don't throw away those seemingly un-chargeable, rechargeable batteries; they could very well be brought back to life with the aid of this simple circuit." (circuit added 9/04)
12V Lead-Acid Battery Monitor: (electronic circuit added 4/05)
A Battery Powered Lap Top Computer Power Supply: DN18 Design Notes (Linear Technology) (app note added 2/06)
AB-32 / Battery Charger Applications: Fairchild Application Notes / (app note added 6/06)
AB-33 / Battery Charger Applications: Fairchild Application Notes / (app note added 6/06)
AB-34 / Battery Charger Applications: Fairchild Application Notes / (app note added 6/06)
AN-4138 / Design Considerations for Battery Charger Using Green Mode Fairchild Power Switch (FPStm): Fairchild Application Notes / (app note added 6/06)
Analog Circuit is Accurate Battery Fuel Gauge: Unpublished 10/98 Circuit acts as a fuel monitor for a rechargable battery, typically NiCd or NiMH chemistries. Analog type needle output meter appears like an automobile gas gauge. (added 9/04)
Automatic Power Off Circuit Saves Battery: 12/05/96 EDN-Design Ideas / (added 9/04)
Battery Characterizer: (Electronic circuit added 4/05)
Battery Simulator Provides Current Limiting : 08/01/97 EDN Design Ideas / (added 5/03) A constant-voltage active load can perform as a battery during the charge cycle. You can set the load voltage from 5 to 35V by using potentiometer PV and thus can simulate batteries ranging from 6 to 32V.
Constant Voltage Load Tests Battery Chargers: 04/11/96 EDN-Design Ideas / (added 6/06)
LED Battery Condition Indicator: (Electronic circuit added 4/05)
Phantom Power Battery Test Circuit: LED will light when battery is over42 volts (added 3/03)
Self-Powered Fast Battery-Tester: Tests 1.5 to 15 Volt cells. Two-LED display, no power supply required (added 3/05)
Simple car battery tester: This circuit uses the popular and easy to find LM3914 IC. This IC is very simple to drive, needs no voltage regulators (it has a built in voltage regulator) and can be powered from almost every.... (added 2/07)
Test Batteries Without a Voltmeter Part 2: 03/15/01 EDN-Design Ideas / (added 11/05)
/ circuit added 05/07)
40 LED Bicycle Light (555 Timer 6 Volt): (circuit added 7/02)
8 Random Flashing LEDs: This project flashes eight LEDs in an apparently random manner. It uses a 4060 combined counter and display driver IC which is designed for driving 7-segment LED displays. The sequence is not really random because seven of LEDs would normally be display segments, eighth LED is driven by an output that is normally used for driving furr counters. The table below shows sequence for LEDs. You can use less than eight LEDs if you wish and table may help you decide which ones to use for your purpose. (added 09/05)
3 Input First Response Monitor: (circuit / schematic design added 6/06)
48kw Resonant Converter for X-Ray Machines Uses High Speed Power Modules With Integral Liquid Cooling: This paper describes an innovative method for the removal of heat from the four IGBT power modules equipping a 48kW ZVS-mode resonant power converter for CT X-ray machines. Application Note Microsemi APT9904 ( app note added 4/08)
An inexpensive x-ray machine: (electronic Circuit / Schematic added 10/04)
Automated Crib Lights: (circuit added 9/04)
Automated External Defibrillator: Intersil Application Block Diagram (app note added 6/06)
Blood Glucose Monitor: Intersil Application Block Diagram (app note added 6/06)
Brain Wave Machine: (electronic circuit added 7/03)
Breath Alcohol Tester Controlling a car ignition system: (electronic circuit added 4/05)
Cardiac Monitor: (electronic circuit added 7/03)
Cranial Electrotherapy Stimulator: Current generated flows through clips placed on the earlobes Output current adjustable from 80 to 600 MicroAmperes (added 9/04)
Digital Step Km Counter Max.: Pedometer has a range of 9.950 meters with2-digits. Slip it in pants pocket for walking and jogging (added 02/05)
EKG/EEG Circuit: (electronic circuit added 7/03)
Electronic Stethoscope (aaroncake): (circuit added 7/02)
Esp Sim (Sound Impairment Monitor): (electronic circuit added 4/05)
AN-1150: COP8 FLASH ISP HANDBOOK-Intro to ISP: National Semiconductor Application Note (app note added 2/06)
AN-1281:Bumped Die (Flip Chip) Packages: National Semiconductor Application Note (app note added 2/06)
CMOS Toggle Flip Flop using Laser Pointer: (circuit / schematic design added 6/06)
CMOS Toggle Flip Flop with Relay(Cd4013): (circuit added 7/02)
Discrete BiStable Flip Flop: (electronic (schematic / circuit added 4/02)
Discrete Set/Reset Flip Flop: (electronic (schematic / circuit added 4/02)
Flip Flop Flashers Buzzers Etc.: (electronic circuit added 7/03)
Follow the Debouncing Flip-Flops: 02/17/00 EDN-Design Ideas / (added 6/06)
High Current MOSFET Flip Flop with Debounced Pushbutton: (circuit / schematic design added 6/06)
Monostable Flip Flops (One Shot): (circuit added 7/02)
Set/Reset Flip Flop: (electronic design added 10/06)
Soft on/Off Switch: Modern electronic equipment incorporate "push-to-on-push-to-off" switches that do not make noise as with old equipment. An example of this is the power button on a ATX computer cabinet. Here is a circuit that does the same. It can be used to turn on/off any electronic/electrical equipment that operates on any range of voltages. When the "ON/OFF" button is.... (added 10/05)
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 User's Guide to I.C. Instrumentation Amplifiers: AN-244 Analog Devices Application Notes (app note added 2/06)
Active Feedback IC Serves as Current Sensing Instrumentation Amplifier: 07)/24/03 EDN Design Ideas / (added 12/04) High-speed current sensing presents a designer with some significant challenges. Most techniques for sensing current involve measuring differential voltage current produces as it flows through a sense element, such as a resistor or a Hall-effect device. The differential voltage across sense element is generally small and is often riding on a common-mode voltage that is considerably ......
AN-202: An IC Amplifier User’s Guide to Decoupling, Grounding, and Making Things Go Right for a Change: AN-202 Analog Devices Application Notes (app note added 2/06)
AN-245: Instrumentation Amplifiers Solve Unusual Design Problems: AN-245 Analog Devices Application Notes (app note added 2/06) Traditionally Considered Only for Transducer-Conditioning Applications, Instrumentation Amplifiers Bring Unique Performance Benefits to a Range of Or Applications as Well.
AN-306: Synchronous System Measures µOs: AN-306 Analog Devices Application Notes (app note added 2/06) Synchronous Detection Scheme Measures Low Resistances
AN-320A: CMOS Multiplying DACs and Op Amps Combine to Build Programmable Gain Amplifier, Part 1: AN-320A Analog Devices Application Notes (app note added 2/06)
Bass-Treble Tone Control Circuit: The LM1036 is a DC controlled tone (bass/treble), volume and balance circuit for stereo applications in car radio, TV and audio systems. An additional control input allows loudness compensation to be simply effected. Four control inputs provide control of bass, treble, balance and volume functions through application of DC voltages from a remote control system or, alternatively, from four potentiometers which may be biased from a Zener regulated supply provided on circuit. Each tone response is defined by a single capacitor chosen to give desired characteristic.….. (added 6/06)
Better Volume Control: how to create a log pot that is better than "real" thing (added 4/02)
Build a Simple Soft Action Muting Switch: 10/14/04 EDN-Design Ideas / (added 10/05) The circuit in Figure 1 adds a soft muting switch with power-up/power-down muting to a line-level audio circuit. R4, C1, and JFET Q1 quietly ground a signal in 100 to 200 msec when you close S1 or release it when you open S1. Potentiometer R2, set to twice Q1's cutoff voltage, makes on/off transition....
Designing with the LMC835 Digital Controlled Graphic Equalizer: National Semiconductor Application Note 04-Nov-1995 (app note added 4/02)
Digital Delay Unit for Surround Sound: (schematic / circuit design added 9/02)
Digital Volume Control has Log Taper: 04/11/02 EDN Design Ideas / (added 12/04) Digital potentiometers provide a compact and convenient way to attenuate audio-amplifier signals. However, most such potentiometers suffer from at least one flaw: a nonlogarithmic step increment. To avoid this problem, a user must usually step the potentiometer in a nonlinear sequence to simulate a logarithmic taper. ...
Digital Volume Control: based on DS1669 Digital Pot IC (added 5/02)
Dual Channel Digital Volume Control: (electronic Circuit / Schematic added 10/04)
Easy Parametric and Graphic Eq's Plus Peaks and Notches: (electronic circuit added 8/02)
Generating Tone using Pdo: Toshiba 870X Series Application Note (app note added 2/06)
Guitar Control: CaStand-alone, 9V battery powered unit . Three-level input selector, three-band tone control (added 3/05)
Test Batteries Without a Voltmeter: 11/09/00 EDN-Design Ideas / (added 5/02) / PDF contains multiple circuits - scroll to find the one of interest / This circuit an easy approach to testing batteries without exiting the voltmeter. The battery holders in sizes AAA, AA, C, and D make this tester so much faster than a voltmeter.
1-Wire Barometer: The circuit requires an additional power source other than that of the 1-Wire network. The 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 the 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. (Circuit / schematic design added 6/06)
Basic Stamp Based Altimeter: A method of determining altitude is by the use of barometric pressure; however, it is not done without difficulty. The relationship of pressure vs. altitude is not a linear one, it is actually a fairly complex one, which the army came up with in the 1930's. This is the equation for calculating .... (Circuit / schematic design added 6/06)
Electronic Barometers: (Electronic circuit added 7/03)
Liquid Barometers: (Electronic circuit added 7/03)
One Wire Barometer: (Electronic Circuit added 03/06)
Portable Altimeter : Todd's Fascination with Flight. Read how Todd designed a portable altimeter using a micro-machined pressure transducer….. Gadget Freak / Design News (Schematic / circuit added 10/05)
Small Portable Altimeter Operates from a Single Cell: 06/21/01 EDN-Design Ideas / (added 5/03)
555 Tone Generator 8 Ohm Speaker: (circuit added 7/02)
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 6/06)
AN16 Automotive and Household Siren Driver Circuits: Zsd100 and Discrete 'H'-Bridge Minimum Parts Count Solution: Zetec Semiconductors Applications Notes A solution is provided that uses a minimum number of components by utilising an application specific signal generation IC, and a high efficiency 'H'-bridge effected with 3A DC rated Super-d TO92 style switching transistors. (app note added 2/06)
Audio MilliVoltmeter: (schematic / circuit design added 9/02)
Automotive and Household Siren Driver Circuits: Zsd100 and Discrete 'H'-Bridge Minimum Parts Count Solution: Zetec Semiconductors Applications Notes A solution is provided that uses a minimum number of components by utilising an application specific signal generation IC, and a high efficiency 'H'-bridge effected with 3A DC rated Super-d TO92 style switching transistors. (app note added 2/06)
Battery Low Voltage Beeper: This circuit provides an audible and visual low voltage warning for 12V battery powered devices. Idle current: 6ma Low Voltage Warning current: 15ma…. (schematic / circuit design added 9/02)
Beeper: This circuit produces sound of a beeper like one in pagers which produces a "beep-beep" sound. Basically circuit consists of a 555 timer oscillator which is turned ON and OFF periodically. The first C (left) oscillates at about 1Hz. The second IC is turned ON and OFF by first IC. The first IC determines how fast second IC is turned ON/OFF and second IC determines tone of final output. By varying VR1, changeover rate can be adjusted. By varying VR2 tone can be adjusted. If you know something about electronics, you can try replacing 2nd 555 IC circuit with a piezoelectric buzzer. This saves one IC and associated components but buzzer cannot give a loud sound as speaker and also its tone cannot be varied. (added 6/06)
Bells Ring Generator: 3-Circuit options Can be synchronized to Christmas tree flashing lights (added 9/04)
Birdie Doorbell Ringer: (electronic (schematic / circuit added 4/02)
Buzzer: (electronic circuit added 8/02)
Continuity Buzzer is Frugal with Power: 04/15/99 EDN-Design Ideas / (added 11/05) [Note: File contains multiple circuits. Scroll to find this one] The continuity detector in Figure 1 is based on
Controller Provides Multiple Alarm Driver Formats: 01/15/98 EDN-Design Ideas / (added 08/05) DC/DC converters for use inside the telephone handset require operation from the high-source-impedance phone line. Additionally, the CCITT specifications call for maximum on-hook power consumption of 25 mA. The dc/dc converter in Figure 1 is 70%-efficient at an input power of 25 mA, providing 5V at 3.4 mA. Controlled, low-peak switch current ensures that the 48V input line experiences no excessive voltage drops during switching.
Cuckoo sound Generator: Agreeable, very close sound imitation Suitable for sound effects, door-bells etc. (added 9/04)
Curious C Beeper: (electronic circuit added 7/03)
Ding-Dong Bell: (electronic Circuit / Schematic added 10/04)
Doorbell for the Deaf: (electronic design added 10/06)
Doorbell with Counter: (electronic circuit added 1/03)
1.5 Volt LED Flashers #1: four circuits with description (added 4/02)
10 Channel LED Sequencer: based on4017 (added 4/02)
10 LED Sequencer: in PDF format, text in Finnish (added 4/02)
10 Stage Light Sequencer: flashes10 low voltage bulbs, operates at10-25-Volt voltage, in PDF format, text in Finnish (added 4/02)
12 Stage Neon Sequencer (NE 2/NE 51): uses small power 70-Volt neon bulbs (added 4/02)
12 Volt Strobe Circuit: this circuit uses12V DC instead od mains AC. This is very good idea if you don't want to mess with direct mains voltage connected circuit or you want to run Strobe from batteries. (added 4/02)
120 VAC Lamp Chaser using Solid State Relays: (circuit / schematic design added 6/06)
120 Volt AC Lamp Chaser using Solid State Relays: This circuit is similar to LED clock using12 neon indicator lamps instead of LEDs. It operates from2 high capacity ni-cad cells (2.5 volts) which keep it going for a couple weeks. High voltage (70 volts) for neon lamps is obtained from a small switching power supply using a 74HC14 Schmitt trigger Squarewave oscillator, high voltage switching transistor, and10 mH high Q inductor. Most any small PNP transistors can be used that have a C/E voltage rating of 80 or more. (added 4/02)
Sound Controlled Flip Flop: Described here is a very inexpensive solution to many phono-controlled applications like remote switching on, for instance, or activating a camera, tape recorder, burglar alarms, toys, etc. The circuit given here employs a condenser microphone as the pick-up. A two-stage amplifier built around a quad op-amp IC LM324 offers a good gain to enable sound pick-up upto four metres. …. (added 10/05)
Spare flip flop stretches WR strobe for DSP: 07/20/95 EDN-Design Ideas / (added 2/06)
Spare gates form edge triggered flip flop: 03/16/95 EDN-Design Ideas / (added 2/06)
Telephone Line Based Audio Muting and Light on Circuit: (added 4/02)
Telephone Line Based Audio Muting and Light-On Circuit: (electronic Circuit / Schematic added 10/04)
Verilog Program Models metastable flip flop: 05/12/94 EDN Design Ideas / (added 11/05)
0.6/1.6 MHz Boost Converters with 22V Inrternal FET Wsitch in SOT-32: National Semiconductor Application Note LM2731 July 2003 (app note added 7/06)
1 Watt 5 Volts Power Booster for the MLX90121: Melexis Application Note (app note added 2/06)
2-Phase Boost Converter Delivers 10W from a 3mm x 3mm DNF Package: DN354 - Design Notes (Linear Technology) (app note added 1/06)
2-Transistor Amplifier: A simple two-stage Amplifier. Use any general-purpose NPN with high gain. It will drive low impedance headphones directly. A speaker will probably require further boost. (added 10/05)
3 Output TFT LCD Bias Supply with a Boost Regulator - MP1542 - DN0005: Monolithic Power Systems, Inc - Design Note - (added 6/06)
3.3V converter delivers 3W from Li-ION battery : 11/05/98 EDN-Design Ideas / (added 11/05) Lithium-ion batteries are rapidly gaining popularity in portable applications because of their superior energy density, low self-discharge rate, and high cell voltage. When you use one Li-ion battery to power a 3.3V dc/dc converter; however, you encounter a problem, because the battery voltage can be higher or lower than 3.3V. When fully charged, a Li-ion cell has approximately 4.2V output; when fully discharged, the voltage is approximately 2.5V. Therefore, you cannot use a simple buck or boost topology with a single inductor to generate a regulated 3.3V output. Some designs boost the voltage to approximately 4.3V and then use a low-dropout regulator to produce the 3.3V. This approach is inefficient, and efficiency is a crucial consideration in battery-powered applications. The circuit in Figure 1 offers a solution to the problem....
3-Band Equalizer: Using a single op-amp this easy to make equalizer offers three ranges, low frequency, mid frequency, and high. With component values shown there is approximately +/-20dB of boost or cut at frequencies of 50Hz, 1kHz and 10kHz. Supply voltage may be anything from 6 to 30 Volts. Maximum boost 20dB is only realized with maximum supply voltage. (added 4/05)
3MHz Micropower Synchronous Boost Converters Deliver 3W from Two Cells in a Tiny MSOP Package: DN246 - Design Notes (Linear Technology) (app note added 2/06)
4-Phase Monolithic Synchronous Boost Converter Delivers 2.5A with Output Disconnect in a 5mm x 5mm QFN Package: DN332 - Design Notes (Linear Technology) (app note added 2/06)
500kHz 6monolithic Boost Converter (LT1370): DN183 - Design Notes (Linear Technology) (app note added 1/06)
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