This circuit was found in a 1980s documentation, using a comparator from the time. The configuration can also be implemented with comparators or modern operational.
This circuit is based on an operational window comparator. We found it in a documentation from the...
This photo-relay uses a Darlington stage to increase sensivity. Any photo-transistor can be used....
This transistor amplifier provides 35 W of power to an 8 ohms speaker and must be powered by a 59...