Frequency to voltage converter (CB6993E)

Found in Popular Electronics from the 90s, this circuit can be used in tachometers. The integrated circuit is not a common component today.

| Clique na imagem para ampliar |

Photometer (CB24120E)
This simple photometer uses a 1 mA milliammeter and a common phototransistor. The circuit has its...
CA3140 3-Scale Voltmeter (CB15504E)
The circuit of the figure allows to implement a multimeter of high sensitivity or even to use a...
TTL signal injector (CB22431E)
This simple circuit must be powered by a voltage of 5 V. The integrated circuit is the 7400, but...