We found this circuit in a 1973 documentation. The null adjustment trimpot is 10k. The circuit can be powered by symmetrical sources from 9 V. The diodes on the bridge can be 1N4148.
This current meter with many scales was found in a 80s American documentation. The operational amplifier...
This dimmer, from an old publication, can use almost any triac and in shooting a neon lamp. The...
We found this circuit in a 1975 publication. The circuit can be made with more modern equivalent...