This 1.5W tube amplifier was found in an American documentation from 1947. It is a direct rectification circuit without the need for a power transformer.
This circuit, from 1999 documentation, prevents the powered device from receiving power when it...
This circuit is intended for monitoring an environment. It fires a relay with a sound, but only if...
Found in a Popular Electronics from the 90's, this circuit uses integrated from that time, today...