This circuit was obtained from American documentation from 1966. It triggers when the two input voltages are within a pre-established range. The circuit can be mounted with modern transistors.
This digitally programmed gain amplifier was obtained from Signetics documentation from the 1980s....
This circuit is from a 60's documentation. The capacitance C1 can be between 20 pF and 0.01 uF...
This circuit was obtained from an American 1980s documentation. The frequency depends on the...