The difference between this circuit and the previous one is that it uses PNP transistors. The circuit is from Radio Electronics magazine from July 1968. The frequency depends on R1 and C1.
July 2017 - Texas Instruments' new 3 A bq25601 single cell battery charger can be found on Mouser...
This circuit was found in old documentation. PUTs are uncommon components today. The circuit...
This simple timer with unijunction transistor was found in an old American technical...