signal tracer and injector

Posted on Feb 4, 2014

A simple test circuit to fault find audio and radio equipment. Can be used to inject a square wave signal, rich in harmonics, or used with headphones as an audio tracer. A single pole double throw sitch is used to switch between inject and trace modes. The diagram is drawn in trace mode, the earpiece being connected to the collector of thelast tra

signal tracer and injector
Click here to download the full size of the above Circuit.

nsistor. Both transistors are wired as emitter followers, providing high gain. DC blocking is provided by the 1n capacitor at the probe end, and the two stages are capacitively coupled. when the switch is thrown the opposite way (to the blue dot) both transistors are wired as an astable square wave generator. This provides enough harmonics from audio up to several hundred kilohertz and is useful for testing AM radio Receivers.

Leave Comment

characters left:

New Circuits



Popular Circuits

Remote-Controlled Switcher
Led Christmas Tree Light Flasher Circuit
hobby power supply circuit
Line Follower Robot
Logic gate using current source and diodes
buzzer only beep once
555 Electronic Metronome Circuit
2 line intercom plus a telephone changeover switch
78xx Voltage Regulators
Using several resistive and capacitive phase shifting trigger circuit
Controllable integrator F007 schematic