Society of Robots - Robot Forum

General Misc => Misc => Topic started by: dex2tek on June 18, 2007, 02:52:34 AM

Title: Help with understanding reverse voltage
Post by: dex2tek on June 18, 2007, 02:52:34 AM

Has anyone built sandwich the robot?, I dont understand how reverse voltage works (flyback diodes), and how the reverse diode is  then hooked up to the motor. If anyone has anyone has any information it would really help

Title: Re: Help with understanding reverse voltage
Post by: Admin on June 19, 2007, 06:40:07 PM

So normally current passes through a transistor/MOSFET in just one direction. If current goes in reverse, bad stuff will happen. With motors, there is a lot of noise. If the motors are suddenly torqued, they apply a voltage to the power lines (noise).

Sometimes this noise is so large that it sends a current in reverse through the transistor/MOSFET, thereby frying it. So what a flyback diode does is allow this 'flyback' current to bypass the transistor and instead go back to your battery.

Does that help?