This circuit is from an article about operations in a Radio Electronics magazine from around 1968. The transistors are types of the time and the power is not the greatest.
This circuit produces the sound of percussion such as blocks, drum, bell, etc. The frequency...
We found this oscillator in a publication from the 1960s. The frequency is around 600 Hz with the...
Found in a Popular Electronics from 1992, this circuit uses a PLL567 in an audio meter bridge that...