Wiring Schematic Diagram

This is a signal injector circuit. Signal injector is important tool for troubleshooting your electronic circuits. As an example, this circuit can be used to test amplifier circuit. Here is the schematic diagram of the circuit:

This circuit also a lot of harmonics. By connecting the ground clip to the 0v rail and move through each stage, starting at the speaker, the fault in an amplifier can be found. At each preceding stage, the volume will increase. This circuit can inject FM sound sections in TV’s and the IF stages of radios.

When T1 conducts, its collector tension goes from high to low. Via C1, this is transmitted to the base of T2 making its collector tension drop from high to low as well. Via C2, this pulse blocks the base-current of T1, causing it to block up. As soon as the left side of C2 is charged enough by R3, T1 can conduct again and the cyclus is repeated.