Optical tachometer (CB9349E)

We found this circuit in a 1970 publication by General Electric. The components can be changed according to the indicator.

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VLF to VHF active antenna (CB6980E)
Found in a European magazine from the 1980s, this circuit can amplify signals from 10 kHz up to...
Generating an Ultra slow Sawtooth signal LM3900 (CB15631E)
The circuit in the figure uses the four current amplifiers of the LM3900 to generate a sawtooth signal...
Nautical megaphone siren (CB23685E)
This circuit is from a Radio Electronics magazine from August 1960. It is a commercial circuit for marine...