We found this circuit in documentation from the 90s. It is a common configuration that is given in two versions, using transistors and using two integrated inverters.
This voice scrambler is used to obtain effects in the 2.5 to 5 kHz range. The circuit is from...
We find this efficient emergency lighting system in a 1987 publication. The circuit keeps a...
The circuit presented is based on the National Semiconductor LM10 operational amplifier, which is not...