This simple bridge circuit can be used for impedance or resistance measurement using a high impedance earphone as an indicator. The circuit is from an American 80's documentation.
This circuit has a logarithmic response as a function of the light falling on the sensor. The...
An OR gate can be implemented with an LM3900 transconductance operational amplifier. The circuit is...
This circuit was found in an American technical manual from the 1980s. The LM111 is an uncommon...