This circuit was found in an American documentation from the 80's. The sensor is a special integrated circuit, uncommon in our times. There are modern equivalents.
This is a two-input audio switching circuit. The operational can be of any type and more entries can...
We found this amplifier for automotive use in the Philips integrated circuit manual from 1990. The...
Found in old English documentation this circuit can be made with a BF245 or equivalent. Coils are...