This signal injector and tracer (follower) was found in an old American documentation. The transistors can be general use and power is made with one or two common cells.
The critical component of this circuit is the transformer. T1 and T2 can be BD135 and T3 / T4 can...
Found in Popular Electronics from the 90s, this circuit can employ other low power audio...
This circuit is from a 1967 publication. It is possible to power a fluorescent lamp from a 12 V...