Dual Sensor (CB21521E)

This circuit, with two operationals, was obtained from an old American publication. Operational amplifiers can be of modern equivalent types.

| Clique na imagem para ampliar |

Delayed Alarm (CB1511E)
This circuit was found in a 1977 Signetics manual. The 556 consists of a 555 double and the...
Process timer (CB21865E)
We found this timer for times of a few minutes in a 1974 Ferranti transistor manual. The relay is 37...
TTL Oscillator with the 7400 (CB518E)
Frequency in this oscillator is given by C1 and C2. The circuit produces square pulses that can...