Simple audio signal injector 2011-07-05

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 found this in the ARRL (Amateur Radio Radio League) Handbook, and adapted it for my purposes. The transistor type is absolutely non-critical:...

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