This sound effect circuit is from a Radio Electronics magazine from December 1969. The transistors support equivalents and the power is provided by a battery to reduce the possibility of noise.
This small general purpose and RF transistor tester appeared in a February 1958 Radio Electronics...
The MC4741 integrated circuit consists of four operational amplifiers similar to the 741 in a...
We found this touch control on a Popular Electronics from 1970. The circuit makes use of an...