With this circuit you can produce the sound effect passing from one channel to another. The circuit is from Mullard documentation from the 1960s. The transistors may be the BC548.
This circuit is from a 1991 PE Hobbyst Handbook. The circuit uses two trigger transformers for a xenon...
A JFET is used in this circuit to maintain constant gain. The circuit is from an Electronics Now...
Found in a Popular Electronics from the 90s, this circuit uses a double 555 to emit beeps when the...