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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
Light, LED/Laser, Output Intensity Meter - This circuit uses a large 1cm X 1cm silicon PIN photo diode and a transimpedance amplifier to measure the light power output of infrared and visible LEDs and laser diodes. It can be modified to produce almost any milliwatts to volts scale factor. It can b . . . Hobby Circuit designed by David Johnson P.E.-July, 2000
Line-Powered Xenon Flash Transmitter - This line powered xenon flash circuit drives a small camera type flash tube. It has an optical isolator to allow the flash to be safely triggered from some remote device. A flash rate of 2Hz is possible with the circuit. . . Circuit by David Johnson P.E.-June, 2000
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 Johnson P.E.-April, 2005
Low Power 40KHz Light Detector - This circuit is designed for detecting infrared light modulated at around 40KHz. It’s feedback scheme cancels much of the DC component from ambient light. It’s conversion factor is about 100 millivolts per microwatt of 900nm light.. . . Circuit by David A. Johnson P.E.-July, 2006
Nitrogen Spark Generator - Nitrogen or air sparks are very powerful light sources that produce flashes that last only a few nanoseconds. This line powered circuit generates a continuous series of very small sparks across electrodes with a 0.05 inch gap . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000
Pulsed LED Test Circuit - This circuit is designed to test visible and infrared LEDs in pulsed mode operations. It can drive the LED with peak currents in excess of 10 amps. A light detector nearby can monitor the response time and intensity of the LED under test. . . Circuit by David Johnson P.E.-June, 2000
RFID Test Circuit - I designed this test the concept of using light techniques to send identification data instead of RF. . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2002
Simple Circuit Nitrogen Spark Generator - Nitrogen or air sparks are very powerful light sources that produce flashes that last only a few nanoseconds. This line powered circuit generates a continuous series of very small sparks across electrodes with a 0.05 inch gap. . . Circuit by Dave Johnson P.E.-June, 2000
Tester for Pulsed LEDs - This circuit is designed to test visible and infrared LEDs in pulsed mode operations. It can drive the LED with peak currents in excess of 10 amps. A light detector nearby can monitor the response time and intensity of the LED under test . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000
Transmitter for Line Powered Xenon Flash - This line powered xenon flash circuit drives a small camera type flash tube. It has an optical isolator to allow the flash to be safely triggered from some remote device. A flash rate of 2Hz is possible with the circuit . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000
Voltage to Frequency Converter + 1us LED Pulse Driver - This circuit receives the signal from the above amplifier and launches powerful 1uS infrared light pulses from a low cost LED that are frequency modulated by the audio information. The 10KHz center frequency of the pulse stream is low enough so a standard. . . Circuit by Dave Johnson P.E.-March, 1999
Xenon Flash Receiver-AIR Transparancy Monitor - I designed this receiver circuit many years ago to monitor the quality of a mile long column of air for future optical communications experiments. The transmitter system (circuit 72 below) uses a powerful xenon flash in conjunction with a large 12 inch . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000
Xenon Flash Transmitter-AIR Transparency Monitor - This is the matching transmitter for the above receiver. The transmitter launches powerful 1000-watt light pulses that last about 20 microseconds . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2000 |
