Found in a 1968 US documentation, this circuit shows how to use the resistance-scale multimeter to analyze the dwell angle of old platinum cars.
This filter that rejects determines frequency (notch) was found in a Popular Electronics of 1993....
Found in an Elektor from the 90's, this double door-bell drive circuit switches a relay by...
Using a 555 this circuit was found in old documentation, but it is still valid. | Clique na imagem...