I am trying to assemble the test circuit for the L298N dual H-bridge from ST. The test circuit documentation is found on page 5 from the following:
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Basically, nothing happens. I'm working on input/output #4. However, I have made a few changes mainly because I don't have all the right parts and am wondering what the problem could be. I put diodes going from 1,15 to ground instead of wire or sense resistors (out of wire, and have no idea what a sense resistor is and/or how to use one). I'm turning on INPUT 4, ENABLE B and VSS (PIN9) via a BASIC stamp 2. Power source is a 12V, 200mA transformer which plugs into the wall (which always seems to be more than 200mA, but i don't know why). I check the voltage and current between the + of the power source and OUTPUT 4 and... NOTHING.
Any insight? Are my modifications messing things up? Are the recommended capacitors CRUCIAL to getting the thing to work?
Thanks Dan! Your suggestions really helped and now I have something working. However, I cannot still get the motor to step. Basically, I'll put HIGH on INPUT 4 and LOW on INPUT 3 (and ENABLE B of course) and I can measure a voltage between OUTPUT 3 and OUTPUT 4. However, no current seems to be present. I really don't understand this, a voltage without current (I have an analog ampmeter who's lowest setting is 5mA and the needle does not move)... I feel like I'm so close!
Any insight would be greatly appreciated! Juliabean
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