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A Weighting Filter for Audio Measurements - For noise measurements. ideal for use with the AC Millivoltmeter above __ Designed by Rod Elliott ESP
Accurate 1hz Generator - Accurate 1Hz squarewave pulses are required in stopwatches and other digital circuits. Here is a low-cost, general-purpose 1Hz signal generator without using a crystal oscillator.230V, 50Hz, single-phase AC mains is stepped...__ Electronics Projects for You
Advertising Badge #1 with Flashing LED - I have seen numerous flashing light badges at trade shows and conventions. They are often handed out as gifts to promote some business. The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by Dave Johnson P.E.-March, 2002
Advertising Badge #2 with Flashing LED - This circuit uses a CD4013 dual D Flip/Flop IC . A single lithium battery will provide months of continuous LED flashing. it also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by David Johnson P.E.-March, 2002
ALD555 Oscillation - Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc
Amplitude-Stable Oscillator Has Low Distortion, Low Cost - 11/09/00 EDN Design Ideas: The multivibrator is a common circuit that consists of an amplifier with both positive and negative feedback (Figure 1a). When the output is positive, the positive. PDF contains multiple circuits, scroll to find the one of interest Design by Moshe Gerstenhaber, Chau Tran, and Mark Murphy, Analog Devices Inc,Wilmington, MA
An Inexpensive Tone Encoder - Figure 1 illustrates an easy circuit that can be constructed with mostly Radio Shack parts on any general purpose circuit board. The only rigid requirement is that capacitor C1 be stable over a wide temperature range. Use only Mylar, Polyester or Metal film for capacitor C1. The frequency is determined by the following formula: FREQUENCY = 1/R1C1The specified values should allow any tone between 100 to 300 Hz. increase R1 or add another resistor in series with R1 for lower tone frequencies __ Designed by Radio Amateur Society of Norwich
An Oscillator Sawtooth & Square Wave Output - Simple, Single Supply and Works Very well with Minimum Parts Count. __ Designed by G.L. Chemelec
Analog LED Bar VU Meter - The circuit was designed to work with an audio power amplifier which operated off +18v-0v-18v power rails. The actual voltage used is not too critical except that the feedback is referred to the LED chain which itself is anchored to a +12v rail, hence the separate stabilizer __ Designed by Richard Torrens
Analog switch converts 555 timer into pulse-width Modulator - 15-Feb-07 EDN Design Ideas: Added CMOS
switch enhances a PWM oscillator Design by Jordan Dimitrov, Tradeport Electronics, Vaughan, ON, Canada
Anton Chekhov - My LO strategy involved mixing a 16.93 MHz xtal oscillator (xtal Q = ~100K) with a 3.121 to 3.216 MHz Hartley L-C VFO. I planned to use the EMRFD Figure 4.24 method to extract low noise + distortion from the xtal oscillator and mix it with the VFO signal in a Gilbert cell mixer like the NE612. __ Contact Vasily Ivanenko
Archery timer - in FiTA-style archery tournaments there are rules to the timing of the event. From the 2000 FiTA rulebook here are the rules that the timer must serve __ Designed by A. Ron Carmichael
Astable Mode Operation 50% Duty Cycle - Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc
Astable Mode Operation Free Running Oscillator - Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc
Astable Multivibrator with Very Low Power - This classic circuit draws only 200 nanoamps from a 1.5v supply . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000
Astable Ultra Low Power Multivibrator - Taking advantage of some new voltage comparators, this circuit can produce a nice square wave signal while drawing only 1.6 micro amps. With the inclusion of a diode, the circuit can also produce short pulses instead of a square wave signal . . . Hobby Circuit designed by David Johnson P.E.-December, 2004
Audio Sweep Oscilator - This circuit was designed for a sound effect, but may serve other useful purposes when a basic, swept-frequency audio source is required. it produces both square and triangular wave outputs that ascend from about 80 to 730 Hertz in a repeating cycle of about 12 seconds. Appropriate component-value substitutions will yield variations in these parameters. Operation is as follows:Operational amplifier U2B and its associated components form an astable multivibrator with __ Designed by Arthur Harrison
Audio Test Oscillator - As a piece of test equipment, an audio oscillator has to be considered essential for anyone working in with hi-fI gear. Together with an audio millivoltmeter (as described in Project 16) , and even better if you have access to an oscilloscope, you will be able to make proper measurements on everything from preamps, RiAA equalisation stages (for vinyl disks) , tone controls, crossover networks, etc __ Designed by Rod Elliott ESP
Auto pulse generator senses & responds to a probed load - 02/25/13 EDN Design Ideas: Use this handy pulse generator to inject momentary power pulses into a circuit under test. Design by Raju Baddi
Automatic Timeout included with this On/Off Flip/flop Circuit - This circuit is ideal when a device needs to be turned on and off with a single pushbutton switch, but also needs to turn itself off after some period of time. With the components shown, the output will stay on for only about 20 seconds . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2012
Band-pass Network - Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc
Basic RF Oscillator #1 - This circuit switches a relay at dark via a Light Dependent Resistor or LDR for short. The applications are numerous. in my application, it switches on a light with an older type movement sensor and is mounted on the top corner of my workshop with the LDR facing upwards. The Dark Activated Relay prevents that the light is triggered during daylight hours. But, it can also be used to switch led-beacon lights for your driveway, or whatever __ Designed by Tony van Roon VA3AVR
Battery-Powered LED Flashing Advertising #2 - This circuit is similar to flashing LED advertising badge #1. it uses a CD4013 dual D Flip/Flop IC . The 74HCT74 IC in #81 does not always work. As in #81, a single lithium battery will provide months of continuous LED flashing. . . . Hobby Circuit designed by David Johnson P.E.-March, 2002
BER Tester Measures Errors in Low-Data-Rate Applications - 12/05/05 EDN Design Ideas: You don't need an expensive pattern generator to produce a PRBS (pseudorandom-bit-sequence] signal for making elementary BER (bit-error-rate] measurements in low-data-rate continuous-transmission systems Design by Cedric Mélange, Johan Bauwelinck, Jo Pletinckx, and Jan Vandewege, Ghent University, Ghent, Belgium
Bipolar current source maintains high output impedance at high frequencies - 12/05/05 EDN Design Ideas: Use line-receiver/amp ICs to build high-frequency constant-current sources Design by Alex Birkett, University College London, Hospital National Health Service, London, UK
Bistable Flip flop - Here are two examples of bistable flip flops which can be toggled between states with a single push button. When the button is pressed, the capacitor connected to the base of the conducting transistor will charge to a slightly higher voltage. When the button is released, the same capacitor will discharge back to the previous voltage causing the transistor to turn off. The rising voltage at the collector of the transistor that is turning off causes the opposite transistor to turn on and the circuit remains in a stable state until the next time the button is pressed and released. __ Designed by
Bill Bowden
Build a PIC Controlled DDS VFO 0 to 6 MHz - This is NOT meant as a detailed building instruction for a DDS VFO. it is only a few fragments from my experimental work in the shack. This is "as is" information. it may contain errors. However, my own prototype works very well. __ Designed by Johan Bodin, SM6LKM
Build a Simple Circuit Complementary-Bracket-Pulse Generator - 20-Aug-09 EDN Design Ideas: When building push-pull switching power converters or motor controllers, you often need alternating pulses with a small amount of dead time between them to minimize simultaneous conduction in output-switching devices. Switching controller ICs have this feature, but they usually operate Design by Horst Koelzow, Global Thermoelectric, Calgary, AB, Canada
Build a UWB Pulse Generator On an FPGA - 06/23/11 EDN Design Ideas: Make pulses that reach twice an FPGA's clock frequency. You can implement a digital UWB (ultrawideband) pulse generator in most FPGAs. The design lets you create a pulsed signal with a frequency that’s twice the FPGA’s clock frequency (Figure 1). A previous design relies on asynchronous delays to make pulses of the desired frequency. That design, however, requires an FPGA that supports tristate pullups, such as the Xilinx Virtex 2 (Reference 1). Design by Punithavathi Duraiswamy, Xiao Li, Johan Bauwelinck, and Jan Vandewege, Ghent University, IMEC/Department of Information Technology, Ghent, Belgium
Bus-Request Signal Generates Logic Waveform - 06/20/96 EDN Design Ideas: The scheme in Figure 1 generates accurate and repeatable logic sequences—even in presence of interrupt activity. Specifically, circuit generates 16-bit logic sequences with a resolution of 100 nsec. This circuit's repeatability is an advantage compared with or sequence-generation methods Design by Dhananjay Gadre, IUCAA, Pune, India
Button Battery Cell Internal Resistance Measurement Circuit - The open cell voltage of a small silver oxide button cell battery remains very close to 1.5 volts over most of the life of the cell. However, there is a relationship between battery health and the internal resistance of the cell. This circuit when used. . . Circuit by Dave Johnson P.E.-July, 2006 |
