This circuit was suggested by National Semiconductor and is present elsewhere on this site. The LM2575 is not very common today and should be mounted on a heatsink.
This circuit, which draws numbers from 00 to 99, was found in an Italian magazine from 1974, but...
This circuit produces two signals with inverted phases. One is taken for the emitter of Q1 and the...
For this function, a little more sophisticated, we need switches (keys) or double sensors. This is...