[SOLVED] what does dual bridge mean?

Sorry for this rather basic question. Reading lots of articles I see the phrase dual bridge or h-bridge etc. Indeed I have a dual bridge driver in front of me now. But what does it actually mean? Is there a good reference for such terms?

Botolph: Sorry for this rather basic question. Reading lots of articles I see the phrase dual bridge or h-bridge etc. Indeed I have a dual bridge driver in front of me now. But what does it actually mean? Is there a good reference for such terms?

Google much? Here is a brief description of what an H-bridge is: http://en.wikipedia.org/wiki/H_bridge

Dual bridges = two bridges.

dhenry: Dual bridges = two H bridges.

The advantage is that you can use the driver to run two motors or devices at the same time.

baselsw:

Botolph: Sorry for this rather basic question. Reading lots of articles I see the phrase dual bridge or h-bridge etc. Indeed I have a dual bridge driver in front of me now. But what does it actually mean? Is there a good reference for such terms?

Google much? Here is a brief description of what an H-bridge is: http://en.wikipedia.org/wiki/H_bridge

Thanks for that, one less thing I don't know. I had been googling dual bridge.

Botolph: Thanks for that, one less thing I don't know. I had been googling dual bridge.

As you explore, you'll typically find two common h-bridge ICs used; these ICs, while not extremely efficient, tend to both be very inexpensive. You'll find many driver boards and shields made with them.

They are the L293 (and the SN745510 drop-in) and L298. Both are "dual h-bridge" chips; the L293 (typically D variant) / SN745510 can handle 1 amp per bridge, maximum, which is useful for many small hobby motors, while the L298 can handle 2 amps per bridge. Generally both of these chips should have a proper heatsink installed to reach the maximum current level.

A couple of other things to keep in mind on the L298: First off, it isn't designed to work on a standard 0.1" pitch breadboard or protoboard. To use it properly (bare) on these boards, you will need an adaptor PCB (I've used this guy's adaptors in the past - they are well made and inexpensive: http://www.jrhackett.net/L298adapter.shtml).

Secondly - the L298 (unlike the L293/SN745510) is designed as a "bridgeable" h-bridge. See the datasheet for more information, but basically what this means is that you can hook it up in a particular fashion to use the two independent bridges as a single h-bridge, which allows you to drive a motor that can pull up to 4 amps.

Finally - the while the L293/SN745510 can't be "bridged" in the same fashion, I have heard (completely anecdotal) of people "stacking" these chips and soldering the legs together to increase the current handling. This isn't defined as permissible in the datasheet for the h-bridge, so YMMV. There is also the issue with getting heat out from the "middle" of the stack...

Also, you need two h-bridges (a dual h-bridge) to drive a bipolar stepper motor. there are also "bridge rectifiers", which are an entirely different things.