Based on Texas Instruments documentation, this circuit is based on the BQ2000 a circuit used to power LEDs. The circuit can be used with lithium-ion batteries.
The original document is from Philiups, but now available from NXP (www.nxp.com), which is the...
If the battery is good, the LED flashes. This simple tester uses an LM3909 integrated circuit. We found...
This negative voltage source was found in a Popular Electronics from the 90's. The transformer has 120V...