The operational amplifier used in this circuit is uncommon nowadays. We obtained this circuit from documentation from the 1980s, but it can be adapted to use more modern equivalents.
This circuit generates trains of pulses in regular intervals determined by R1 and C1. The...
The first transistor can be the BF494 and the other BC548 on this MW radio found in a...
We found this circuit in a Popular Electronics from 1992. It modulates an infrared LED with a...