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.
This circuit was found in an American documentation from the 60's. The transistors are from the...
This oscillator is indicated for the adjustment of FI of FM radios, having its frequency...
This configuration triggers an external circuit or simply an LED for time given by R1 and C1 (T =...