The transistors in this circuit can be the BC548 and it also functions as a logic function. The supply voltage depends on the circuit to be excited.
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...