This circuit was found in ancient American documentation. It provides a 70 Vpp signal at frequencies up to 100 kHz. Observe the high supply voltage.
We found this configuration in a documentation for radio amateurs from 1974. The circuit can be...
This circuit for car engine spot adjustment was found in an 80's Radio Electronics. The circuit...
This circuit applies to an old dial phone by detecting light pulses in the dial. The circuit is...