We found this circuit in the Linear Applications Handbook of the 1994 National Semiconductor. The transistor must be a high voltage type and the LM3900 power supply must be symmetrical.
June 2017 - The new touch switches C & K KXT series can now be obtained from Mouser Electronics. These...
We found this 555 integrated-circuit tester in an old Electronics Hobbyst from 1977. The circuit is...
This circuit was found in a 1997 documentation. The signals are adjusted in a double 555 (556) and the...