Found in American documentation from the 1980s, this circuit has a diode feedback. At the exit we have an indicator LED. The LM3900 is a transconductance operational amplifier.
Found in Motorola documentation from the 1980s, this circuit employs an integrated device from...
This input circuit for an oscilloscope was found in Radio Electronics from the 90s. The operating...
This circuit was found in Motorola documentation from 1968, using high power transistors and...