This current meter with many scales was found in a 80s American documentation. The operational amplifier is from that time, uncommon nowadays.
Found in a 1967 Delco documentation, this circuit can deliver power from 40 to 50 W at 8-ohm load....
This configuration, which requires a symmetrical power supply for the 741, can be implemented with other...
With a 1 500 uFcapacitor this timer can reach times up to one hour. The capacitor must be of good...