We found this circuit in an old Popular Electronics. The circuit is experimental, driving an LED from signals applied to the LDRs. The power supply does not have to be symmetrical.
Obtained from a 1967 documentation, this circuit uses transistors from the time. The galvanometer can be a...
Motors up to 2 A can be controlled by this circuit, which requires a symmetrical source. Although...
This sensitive MW receiver was found in a publication of year 1958., The circuit uses germanium...