Actually in one of my projects, I need to rotate same DC motor in both directions(forward/reverse).
Should I control direction of motor by using 5V relay instead of using a MOSFET and a diode.
Can be done using a DPDT relay, but not with individual MOSFET and a diode.
Paul
"Actually in one of my projects, I need to rotate same DC motor in both directions(forward/reverse)."
You probably could do that with just two relays if you don't need motor speed control.
But most of us would probably use an H-bridge motor driver. There are many available.
Steve
You always need an H-bridge(*), whether its implemented as a DPDT relay or 4 MOSFETs or transistors/diodes is a decision you have to make.
(*) For bi-directional control of a motor from a single supply.
"(*) For bi-directional control of a motor from a single supply."
You sure about that? Just curious why an H-bridge would be required.
zoomkat:
"(*) For bi-directional control of a motor from a single supply."You sure about that? Just curious why an H-bridge would be required.
Do you have an alternative?
Paul
"Do you have an alternative?"
Well, one might use two SPDT relays with each motor lead connected to a relay common. A + and a - from the power supply is connected to each relay throw, with the - connected to the NC contacts of the relay. With the relays deenergized, both motor leads are connected to the power supply -. When a relay is actuated its pole moves and makes contact with the power supply +, causing the motor to run in one direction. When the other relay is actuated, the same thing happens and the motor runs in the opposite direction.
Been there and done that and it works well until the Chinese relays crap out. Just a "mechanical" h-bridge.
Paul
Paul_KD7HB:
Been there and done that and it works well until the Chinese relays crap out. Just a "mechanical" h-bridge.Paul
zoomkat:
"Do you have an alternative?"Well, one might use two SPDT relays with each motor lead connected to a relay common. A + and a - from the power supply is connected to each relay throw, with the - connected to the NC contacts of the relay. With the relays deenergized, both motor leads are connected to the power supply -. When a relay is actuated its pole moves and makes contact with the power supply +, causing the motor to run in one direction. When the other relay is actuated, the same thing happens and the motor runs in the opposite direction.
That's an H-bridge implemented with relays, I said this already in post #4
You need 4 SPST, 2 SPDT or 1 DPDT switches. A transistor or MOSFET is the equiv. of a SPST, so you need 4 of them.
If you have a dual voltage supply you can get away with two SPST switches or one SPDT.
"That's an H-bridge implemented with relays, I said this already in post #4"
My thoughts from way back on the subject.
