This circuit was found in a 1969 Mullard documentation. Used transistors can be replaced with modern equivalents. Output transistors may be BD135 and 136 with heatsinks.
In this application we use an additional input circuit to enable the logic command with keys,...
This ultra-low frequency receiver circuit was published in the August 1973 issue of Radio...
This amplifier was obtained from the CA3140 datasheet, an operational amplifier with JFET at the...