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.

CC2564C Dual Mode Bluetooth Driver
March 2017 - Mouser Electronics is sourcing the new Bluetooth Driver CC2564 from Texas...
Simple Diode Tester (CB4149E)
This circuit is from an 80's publication. It makes use of small 6 V x 50 mA incandescent lamps....
Charge Current Monitor (CB5286E)
This circuit makes use of the Linear Technology LT6100. We find it in a 2005 company manual. The...