Indicated by Texas Instruments, this 1968 circuit measures the duration of a light pulse captured by a phototransistor. Equivalent phototransistors and transistors may be used.
With this circuit it is possible to obtain an AND gate with large fan-in, using an operational...
This circuit is from a technical manual of the 80's. The operational ones are of the time like the...
We found this filter in a Popular Electronics from 1993. The operational amplifier can be the 741....