Found in a 1969’s EDN, this circuit provides 4.5 V with a 100mA current for digital logic. The circuit uses transistors from the era.
This circuit was found in Philips documentation from 1967. The phototransistor is from that time,...
We found this third-order Butterworth asymmetric filter in an old manufacturer documentation. The...
We found this circuit in a publication for radio amateurs of 1976. The operational amplifier is a...