Found in a Popular Electronics from the 90s, this circuit activates a recorder for automatic recording of telephone calls. The circuit was used with old cassette recorders of the time.
The figure shows how to obtain a locking relay for an alarm circuit with sensors in series and in...
Found in Popular Electronics from 1969, this circuit uses a neon lamp from the time that had...
This is a simple rheostat circuit for motor control that works with voltages from 6 to 12 V. The...