Dc motor driver circuit or relay

[hamid159]

hi everyone,
i'm working on a robot.i'm using rx28 and tx2b as receiver and transmeter respectively.is there is benefit of using driver circuit against relays.i have a 12V battery.should i use driver circuit like pwm full bridge or only relays?i want constant speed not variable.

 

[chuckey]

Relays (2, on/off, forward/reverse) simple. Full bridge plus drivers - complicated.
Frank

 

[hamid159]

Thanks chuckey.

 

[kam1787]

although relays consume more power, slower[not that it matter here], can stick

 

[mrinalmani]

If you want a constant a speed then the most cost-efficient and reliable method would be to use solid-state switches (eg MOSFETS) because:
1. Relays are more prone to faliure.
2. A good quality relay is far more costly than a MOSFET of the same current and voltage rating.
3. Relays will suffer from severe sparking, in case of an inductive load (motor, in your case)
4. Pre-amplifier is required (additional cost) for driving the relay from a micro-controller. A MOSFET my be driven directly from the micro-controller.

 

[hamid159]

hy mrinalmani,,,how can we prevent the relay from sparking due to inductive current..relay energizes and de-energizes fastly in case of motor can you please suggest me what should I want to do to prevent sparking