The circuit presented was obtained in a technical documentation from National Instruments. The low-consumption circuit supplies a common LED with a voltage of just 1.5 V.
November 2016 - Already available from Mouser Electronics on Texas Instruments' new DS280BR820...
This circuit generates a pulsed tone whose frequency depends on C2 and whose flashing depends on...
The presented circuit is suggested by National Semicondictor in its 1994 Linear Applications...