If the battery is good, the LED flashes. This simple tester uses an LM3909 integrated circuit. We found this configuration in an old documentation.
This circuit is from the National Semiconductor's Linear Applications Handbook of 1994. The...
This RF signal meter has a switch position that allows calibration and comparison of low intensity...
T We found this circuit in the 1960 Mullard transistor application manual. The circuit can be...