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Bazz4CQJ · 29th Oct 2020, 3:24 am

OK, I've actually found the two circuits, which appeared in Elektor, September 1976. Just so that we stay on topic, these are circuits with variable delay switching for any application.

The first is a 555 which operates a relay. The second is a 2N2646 unijunction transistor (still available) which triggers an SCR, which switches on the load, but that circuit expects the load to switch itself off at some point in order to cycle.

As I want to cycle about every 10-20 seconds for long periods of time, the idea of using a relay in the year 2020 sounds a bit "clunky", but it would be a pretty sure-fire place to start. The relay would certainly allow easy swopping between solenoids of either 12 or 24 volts, which would be a very nice to have feature to begin with.

B

29th Oct 2020, 3:24 am	#28
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	Re: 12VDC power switching circuit OK, I've actually found the two circuits, which appeared in Elektor, September 1976. Just so that we stay on topic, these are circuits with variable delay switching for any application. The first is a 555 which operates a relay. The second is a 2N2646 unijunction transistor (still available) which triggers an SCR, which switches on the load, but that circuit expects the load to switch itself off at some point in order to cycle. As I want to cycle about every 10-20 seconds for long periods of time, the idea of using a relay in the year 2020 sounds a bit "clunky", but it would be a pretty sure-fire place to start. The relay would certainly allow easy swopping between solenoids of either 12 or 24 volts, which would be a very nice to have feature to begin with. B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch.