Switch electric polarity back and forth at least several times per minute?

I've seen a polarity inverter switch, but is there an automated version of one available that would switch the polarity continuously back and forth without needing to do it manually?

Thanks


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iceng23 days ago

The 8 pin 555 IC will adjust the timing by adjusting R1 and C.

http://www.bowdenshobbycircuits.info/555.htm

The
Seandogue dpdt recommended relay reverses the polarity to ==> in
this case a small DC motor and will work from 5 v to 15 v DC

Click the pic to see the whole image...

RevRly.GIF

Why not use mains power? Or mains power through a transformer? The mains power voltage changes polarity, back and forth, 3000 or 3600 times per minute, which is 50 or 60 times a second, which is 50 or 60 hertz.

Maybe that is too fast?

If "several times per minute" means approximately 10 times per minute, then maybe you need to build the inverter yourself, using one of the techniques other answerers have suggested: H-bridge, DoublePoleDoubleThrow (DPDT) relay...

https://en.wikipedia.org/wiki/H_bridge

https://en.wikipedia.org/wiki/Relay

A slowly turning wheel with some cams riding on it, might work too.

https://en.wikipedia.org/wiki/Cam

rickharris24 days ago

In general a solenoid (your electromagnet) is one way and the return is by spring pressure. So when you pulse the coil the armature sucks in when you turn the coil off the armature is pushed back out by a spring.

HOWEVER if you want Bidirectional current than you need to check out the circuit for an H Bridge.

https://www.google.co.uk/search?q=H+bridge+circuit...

nlogic (author) 24 days ago

Thanks for the responses. I must confess, I'm new to this site and I don't know much of anything about electronics. What I'm trying to do is set up an electro magnet that automatically flips the field back and forth. I thought that the simplest way to do it would be to alternate the direction of the current.

seandogue24 days ago

dpdt relay and a clock circuit is a common method for producing the desired result.

luxstar24 days ago
luxstar24 days ago

http:/www.cancertutor.com/cancer02/bobBeck-Schematics.html

iceng24 days ago

Yes. What for ?