This filter has the components calculated for the frequency of 1 kHz but can be changed. The input resistor can be 100k and the source symmetrical. Any operational amplifier can be used.
This bistable touch circuit using CMOS technology controls a relay. The supply voltage must be...
This project is from the book Science Fair Projects by Newton C. Braga. In it we have a relay that...
This circuit was obtained in an old documentation, but it is still current by the used components....