INFRARED_CODE_PRACTICE_TRANSMITTER

Published:2009/7/12 20:46:00 Author:May | From:SeekIC

A 555 timer, IC1, is connected in an audio-oscillator circuit with its frequency set by potentiometer R6. Transistor Q1, with the CW key up, is biased on, thereby holding pin 5 of IC1 low and keeping it turned off. The 555 timer's output, at pin 3, ties to the gate of a power hexFET, Q2, which drives the three IR emitters, LED1 to LED3. Placing the CW key in the down position turns the 555 oscillator on. That sends out the audio tone signal via IR.



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