Low battery indicator 555 (CB9551E)

This circuit can operate with different voltages, depending on the zener used. We found it in a 90s American documentation.

2 complementary-transistor oscillator CB22390E (CB22390E)
This LC oscillator with complementary transistors was found in an English publication from the...
Two-Phase Generator (CB208E)
This circuit generates two signals in phase opposition. The frequency is determined by R1 and C1...
Voltmeter 200 k ohms per Volt (CB18923E)
We found this circuit in an old documentation from the 80's. The integrated circuit used is an...