For measurements between 30 and 40º C this circuit was found in the documentation of 1968. The sensor is a difficult component to obtain today.
This simple metronome, from 1985 documentation uses only transistors and has two settings. For...
This circuit is suitable for modulating AM transmitters. The circuit is from a 1977 radio amateur...
This flasher was found in an old Hands On, but uses common components. The optocoupler can be...