This circuit is from American documentation from 1970. It can be designed with a BC558 and for the operational, we can use equivalents. The FET can be the BF245.
This circuit functions as a thermostat triggering a relay when the boil control temperature...
The circuit presented is quite simple, employing tone modulation of the signal. To receive the...
El circuito de la figura es sugerido por National Semiconductor y puede servir de base para una...