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.
This circuit is from a technical documentation from Texas Instruments from 1978. In it we have the...
We found this circuit in a publication with experiments with operational amplifiers from 1973. The...
Using a varactor or varicap, this 1969 Electronics World circuit has a modulation range from 75...