The tone generated by this bell changes when we press and release the switch. The circuit is from a 1985 Radio Electronics. Some changes can be made to improve its performance.
In this circuit, from a 1977 publication, we have the traditional version of a filter that rejects 1...
The integrated circuit used in this application is uncommon today. However, the basic...
This physical line servo control uses components that are not currently common. The circuit is from...