We found this circuit in an old documentation, but the components used offer no difficulty in obtaining it. The CMOS integrated circuits are powered by a 6V supply.
In the figure we have a typical polarization circuit for MOSFETs with a high impedance...
Found ina 1970 American documentation this fast-reading circuit uses a photodiode. Transistors...
Found in a 1970's Radio Electronics, this circuit uses a triac to switch loads on the AC network. This...