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 integrated circuit used in this project is not common today, but it can be implemented with more...
Found in an American publication from 1969, this circuit can be adapted to be used as a shield....
This current meter with many scales was found in a 80s American documentation. The operational amplifier...