This circuit was found in an Electronic Design. It makes use of a relaxation oscillator to trigger an SCR and two relays. The circuit operates at frequencies of 12 to 180 cycles per minute.
This adjustable oscillator has the traditional configuration already presented in other articles. The...
The transistor can be the BD135 and this circuit, found in a 1978 publication, can be powered by...
Found in a Popular Electronics from the 90s, this circuit activates a recorder for automatic...