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.

40 mA Constant Current Source (CB6632E)
The setting of this power supply is only 0.1%. We found it in a 1969 US documentation. Transistors...
Electronic die (CB21712E)
This circuit is based on a common cathode 7-segment display. The circuit is based on CMOS...
1000 second timer (CB23601E)
The existence of field effect transistors at the input of the integrated circuit (operational...