P1 on this Radio Shack circuit is a 6 V lamp with current up to 500 mA depending on Q2. The frequency is given by C1 which can have a modern standard value such as 3.3 uF or even 4.7 uF.
We found this touch control on a Popular Electronics from 1970. The circuit makes use of an...
This very low frequency circuit was found in a 1964 Electronic Design. Transistors may be modern...
This circuit, from the 1990 Motorola Dataar Databook, can be implemented with other comparators. The...