I'm trying to drive an electromagnet with a 556 timer in a push pull configuration. The magnet has to change polarity rather quickly and sharply about 10 to 20khz. The voltage also has to be variable, between 3 to 15 volts the current draw is in the range of 1amp. What I need is a way to amp the square waves, I was thinking of using a pair of relays driven by the 556 timer in the complimentary configuration that way I can feed through them a varying voltage independently without affecting the 556... Or am I going at this the wrong way?
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3\$\begingroup\$ Relays won't get you anywhere close to 20kHz. \$\endgroup\$– Kevin VermeerCommented Aug 2, 2010 at 21:03
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1\$\begingroup\$ What are you doing with the magnet? \$\endgroup\$– starblueCommented Aug 2, 2010 at 21:55
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1 Answer
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You need to build or buy something called an H-bridge. They are commonly used for motor control.
answered Aug 2, 2010 at 18:17
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\$\begingroup\$ Try the National LMD18200D, or a kit that lets you connect to one. \$\endgroup\$ Commented Aug 2, 2010 at 19:00
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\$\begingroup\$ @pingswept: that's a nice part, roughly like the L298N, but diodes included. \$\endgroup\$– JustJeffCommented Aug 3, 2010 at 2:36
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\$\begingroup\$ I tried a H-bridge made by Cana Kit and it works like a charm! I'm still using the 556 timer in complimentary configuration mode and it works perfectly. Thank you very much for the advice Joeforker! \$\endgroup\$– ChippyjamesCommented Aug 4, 2010 at 22:21