This circuit from the 60's uses germanium transistors of the time. Listening is done on high impedance headphones.
Found in a PE Hobbyst in 1991, this 13.6 V power supply with a 2 A current is suitable for supply...
This signal injector and tracer (follower) was found in an old American documentation. The...
The Variable Frequency Oscillator (VFO) shown in the figure can generate signals in a frequency...