This circuit was found in 1960s Radio Electronics. The circuit uses components from that time. The triac is according to the controlled load. The sensor is a common LDR.
Nothing more useful on the bench than a variable voltage source. This is the source we found in...
We found this circuit, which appears with variations on this site, in a European documentation from the...
This circuit is used to fire an auxiliary flash when the machine's main flash operates. With two...