This ingenious circuit was found in a 1990s Popular Electronics. The oscillator is a 555 and the keyer uses an optocoupler in the configuration shown.
The integrated circuit used is no longer common today. The circuit is from Motorola's 1990 Linear...
This circuit from the 90s, found in an Electronic Engineering can be used as a shield since its...
Turns Ratio Between Windings Impedance Ratios 100:1 10 000:1 99:1 9 801:1 98:1 9 604:1 97:1 9...