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Alternating polarity from single trigger

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Mac

New Member
:?: Can anyone help me take a single signal from a timer and make it alternate 2 relays to swap polarity to a linear actuator for fwd and reverse? I've researched flip flops but remain confused!
 

Gene

New Member
How about following the timer with a 40xx counter (not binary) with the reset on the second count. Count one activates relay #1, count two activates relay #2, then reset for the next pulse from the timer chip?
 

Mac

New Member
40xx meaning 4051 or similar pic? I'm not real familiar with all terminology as I'm a beginner and there's a lot to absorb.
Thanks,
Mac
 

Gene

New Member
I was thinking along the lines of a 4017. There's a schematic posted here

http://www.electro-tech-online.com/threads/ir-remote-control-extender.641/#post-3088

where two 4017s are put together to get a higher count than what you need. But, if you study the diagram and pull the data sheet on this IC you will get the jist of how it sequences and how it is forced to re-set at any predetermined point in the count.

There are other counters available worthy of consideration. Also, you may need a transistor switch to drive your relays since your IC output is rather weak.

A flip-flop driving a DPDT relay is another option worthy of your consideration.

I think a PIC is far too complicated for what you are trying to acomplish.
 
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Phasor

Member
There is the flip-flop option, which I have shown below - the FF is half of a 4013 (dual D-type FF).

Alternatively, you may be able to use a "latching" relay. They're not very common, but are sometimes useful, if you can get hold of one. The relay is mechanically configured, so that it changes state when the coil is energised, and holds that state after power is removed from the coil. When you energise it again, it switches to the other state (and holds it). You can drive it directly from your signal (if it can supply the current) or via a transistor.

NB For the latching relay to operate correctly, the signal pulse needs to be fairly long - at least 100mS, maybe more - check the specs of the relay.
 

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stevez

Active Member
I was thinking that a NOR gate or 2 input NAND with inputs tied together

An "OR" operates so that output is "on" if one or the other input is "on".

The "N" in "NOR" indicates the "not" function so the NOR output is off when the input is on, and on when the input is off.

Bear with me, I am dredging this stuff up from memory and may be a little off.
 

john1

Active Member
Hi Mac,

Is this 5.5 volt logic stuff ?
or higher voltage units ?

John
 
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