This circuit was found in Motorola documentation from the 1980s. PUTs are not common components today and lamp power depends on the SCR.
We found this circuit in an Electronic Design from the 80's. The generated tone can be changed as well...
This basic tone control circuit employs a Philips NE5538 operational amplifier, but can be adapted to work...
This two-phase stepper motor circuit was found in an old documentation using an operational amplifier...