Simple Audio Signal Injector

Posted on Feb 5, 2014

Here`s a signal injector for those of us like me who don`t have a bench full of nice test equipment. It can be used for tracing audio circuits for troubleshooting, or for working on audio circuits that require some kind of signal for testing. The injector is a single-transistor implementation of the classic twin-T oscillator circuit. I actually fo

Simple Audio Signal Injector
Click here to download the full size of the above Circuit.

und this in the ARRL (Amateur Radio Radio League) Handbook, and adapted it for my purposes. The transistor type is absolutely non-critical: any small-signal NPN transistor will do. Likewise, component values aren`t crucial, and you can change them for different frequency output if you like. (As built, the injector gives about a 1 kHz tone at about 1v p/p. )

Leave Comment

characters left:

New Circuits



Popular Circuits

Razor-sharp CW filter
Low voltage detector
live wire sensor
build varying brightness ac lamp circuit
water detector circuit for your
Flip-Flop Timer Using 4017
Ponyprog Circuit for ATMEL AVRs
Brovin Kacher Tesla
Intro to Intan Amplifier Chips
Space Charge and Low-Voltage Tubes
FM radio tuning circuit circuit
CS37-2 machine tube feeding circuit diagram