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Signal Generator Circuits

Signal Generators:  #'s - B        C - L       M - S       T - Z
 

Last Updated: December 31, 2017 10:33 AM

Circuits Designed by Dave Johnson, P.E. :

LC Oscillator Medium Power 125Khz -  This circuit is similar to MEDiUM POWER 125KHZ OSCiLLATOR but adds even more inverters in parallel to deliver yet more power.  The values shown are for 125KHz . . . Hobby Circuit designed by David Johnson P.E.-March, 2002

LED Flashing Badge #1 -  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 David Johnson P.E.-March, 2002

LED Flashing Badge #2 -  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 A. Johnson P.E.-March, 2002

LED Test Signal Generator-40Khz -  This 40KHz crystal controlled oscillator circuit drives an infrared LED with powerful 40ma pulses.  The circuit can be used to test optical communications circuits, designed to receive 40KHz modulated light signals . . . Hobby Circuit designed by David A. Johnson P.E.-February, 2002

Light to Frequency Converter -  This circuit uses a CMOS version of the classic 555 timer, to form a light intensity to frequency converter.  A small PIN photo diode is used as the light detector.  The pulses produced are short, so in some applications you may want to stretch them or . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2008

Low Battery Voltage Flasher -  This circuit is designed to monitor two alkaline cells (3v) that form the battery often used in portable electronic equipment. . . Circuit by Dave Johnson P.E.-January, 1998

Low Frequency Oscillator draws only 2 Nanoamps -  if you have hundreds of touch switches that need an excitation signal, then this circuit is what you need.  its 20KHz 20v peak to peak output signal can supply up to 3 watts of touch switch excitation power. . . Circuit by David Johnson P.E.-July, 2006

Low Power 100khz Light Receiver -  By starving a high speed logic inverter for current, this circuit can produce a sensitive 100KHz light receiver circuit, which is immune to ambient light, but only drawing 100 micro amps from a 3 volt supply. . . Circuit by David A. Johnson P.E.-April, 2005

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-368-7747




Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

LC Colpitts Oscillator operates on 0.5V to 5V Single Supply -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

LC Oscillator has 1% THD -  03/31/94 EDN Design Ideas:  At the heart of many oscillators is a parallel-resonant LC tank circuit whose impedance is infinite at the resonant frequency of 1/2[pi]ÖLC Hz.  infinite impedance implies an absence of parallel damping resistance, so once an ideal tank circuit __ Circuit Design by Gary Sellani, Maxim Integrated Products, Sunnyvale, CA

LC Oscillator has stable Amplitude -  10/27/05 EDN Design Ideas:  Simplified design offers low distortion, self-adjustment __ Circuit Design by Julius Foit, Czech Technical University, Prague, Czech Republic

LC Oscillator Medium Power 125Khz -  This circuit is similar to MEDiUM POWER 125KHZ OSCiLLATOR but adds even more inverters in parallel to deliver yet more power.  The values shown are for 125KHz . . . Hobby Circuit designed by David Johnson P.E.-March, 2002

LED Flashing Badge #1 -  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 David Johnson P.E.-March, 2002

LED Flashing Badge #2 -  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 A. Johnson P.E.-March, 2002

LED Test Signal Generator-40Khz -  This 40KHz crystal controlled oscillator circuit drives an infrared LED with powerful 40ma pulses.  The circuit can be used to test optical communications circuits, designed to receive 40KHz modulated light signals . . . Hobby Circuit designed by David A. Johnson P.E.-February, 2002

Light to Frequency Converter -  This circuit uses a CMOS version of the classic 555 timer, to form a light intensity to frequency converter.  A small PIN photo diode is used as the light detector.  The pulses produced are short, so in some applications you may want to stretch them or . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2008

Light to Frequency Converter -  Fout = –1.4kHz per microampere of photo diode current, iPD.  The LTC6990 is a precision silicon oscillator with a programmable frequency range of 488Hz to 2MHz.  it can be used as a fixed-frequency or voltage-controlled oscillator (VCO).  The LTC6990 is part of the TimerBlox family of versatile silicon timing devices.  A single__ Linear Technology/Analog Devices App Note, Jun 16th 2010

Linear ramp generator uses one op-amp -  EDN Design Ideas:  01/26/2015    Get integrator-like ramps that know when to stop __ Circuit Design by Einar Abell

Linkwitz Cosine Burst Generator -  Based on work done by Siegfried Linkwitz (reproduced with his permission)  __ Designed by Rod Elliott  ESP

LM324 Pulse Width Modulator -  Schematic only, no circuits description.   __ Designed by Tony van Roon  VA3AVR

Load Pulser Tests Supply's Transient Response -  04/11/96 EDN Design Ideas:   Modern µPs place severe demands on the transient response of the power source.  For example, intel's P6 specification stipulates an output-current capability of at least 30A/µsec while maintaining output-voltage regulation within specified limits __ Circuit Design by Chester Simpson, National SemiConductor, Santa Clara, CA

Low Battery Voltage Flasher -  This circuit is designed to monitor two alkaline cells (3v) that form the battery often used in portable electronic equipment. . . Circuit by Dave Johnson P.E.-January, 1998

Low Distortion Crystal Oscillator -  This crystal oscillator is designed to operate with fundamental crystals with less than 1 mW dissipated in the crystal.  The signal current is filtered by the crystal and develops a voltage across a capacitor with about 500 ohm of reactance.  The resulting sinewave has low distortion and phase noise.  A JFET  buffer is included to drive lower impedance loads.  Further buffering with an emitter follower and a  voltage step-down transformer or matching network is recommended for driving 50 ohm loads.  C3 may be reduced for larger output voltage or to allow lower drive level or it may be increased when lower output levels are desired __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Low Frequency Oscillator draws only 2 Nanoamps -  if you have hundreds of touch switches that need an excitation signal, then this circuit is what you need.  its 20KHz 20v peak to peak output signal can supply up to 3 watts of touch switch excitation power. . . Circuit by David Johnson P.E.-July, 2006

Low Frequency Sine Wave Generator -  The two circuits below illustrate generating low frequency sine waves by shifting the phase of the signal through an RC network so that oscillation occurs where the total phase shift is360 degrees.   __ Designed by Bill Bowden

Low Power 100khz Light Receiver -  By starving a high speed logic inverter for current, this circuit can produce a sensitive 100KHz light receiver circuit, which is immune to ambient light, but only drawing 100 micro amps from a 3 volt supply. . . Circuit by David A. Johnson P.E.-April, 2005

Low-cost 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 __ Circuit Design by Cedric Mélange, Johan Bauwelinck, Jo Pletinckx, and Jan Vandewege, Ghent University, Ghent, Belgium

Low-distortion Audio-range Oscillator -  Generates very low-distortion sine waves up to 1V RMS No thermistors required No settling time __ Contact Flavio Dellepiane, fladello @ tin.it

Low-Distortion Oscillator Starts Fast -  05/26/94 EDN Design Ideas:  Unlike a Wien-bridge oscillator, the phase-shift oscillator in Fig 1 starts up quickly.  Also, the circuit does not require that you adjust several trimming resistors just to tune the oscillator to a given frequency.  Experiments show that the circuit's total harmonic distortion (THD]measures __ Circuit Design by Mika Maaspuro, Helsinki University of Technology, Espoo, Finland

Low-Frequency Crystal Controlled Oscillator -  The RF engineer sometimes has to look for an instrument that will check a low frequency quartz crystal unit reliably and rapidly.  This is a difficult piece of equipment to find and the engineer often has to consult an electronic circuits handbook for the schematic of a circuit that will perform the task.  Unfortunately __ Designed by Ramon Vargas

Low-Pass Filter RFI Filter -  Circuit ideas for Designers App Note__ Advanced Linear Devices, Inc

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Signal Generators:  #'s - B        C - L       M - S       T - Z


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