problem in driving servo motor from microcontroller port pin

servo motor with 8051

i m using 8051 microcontroller and driving servo motor from its port 2 pin. but motor does not start and port voltage is 3.86 volt . when i connect motor to 3V power supply it runs. plz tell me intermediate circuit between motor and port pin to drive the motor.

microcontroller to servo connection circuit

you must use transistor to drive current to the motor you will connect the uc pin and the transistor can work as emiter follower

pchannel drive microcontroller

You should never connect microcontroller pin(s) to a device such as a motor .. These pins are designed to drive buffers, sometimes directly LEDs or CMOS/TTL gates, but are not desgned to cope with inductive loads.
After all, they can "consume" only some mA of current in sinking configuration and produce next to nothing in source configuration ..
From what you described you want to drive this motor with one of its poles connected to 0V. This can be done with its other pole fed by PNP or P-channel mosfet transistor driven by 8051 output pin and inverted logic to control this pin. Obviously you will need a couple of resistors connected between 8051 pin + base of PNP + 5V .. to drive this transistor ..
Btw, what is the current required by your motor?
Regards,
IanP

8051 servo motor

hi

can i use buffer instead of transistor,as i am using 4 servos,to reduce circuit interface,if so what buffer can i use

thanks for help

microcontroller programming driving servo motor

I think that buffer will not work as buffers works with the idea of microcontroller ports you must use transistors "TIP131" is a comon one in motor driving circuits

microcontroller motor problem

hi

thanks too much for your help,but what is the supply voltage of the TIP131

i am using it in a autopilot system so max voltage i can supply is only 5 v

and my servos are just rc servos

thanks

u might wana check the ground connection of the microcontroller and the servo..i had just the same problem then..

Re: problem in driving servo motor from microcontroller port

hi

at last the problem was in the power of the circuit ,when replacing the battery with a high power one the servos work well

thanks too much for your help

Re: problem in driving servo motor from microcontroller port

Hello .

m using 8051 microcontroller and driving servo motor from its port 2 pin. but motor does not start and port voltage is 3.86 volt . when i connect motor to 3V power supply it runs. plz tell me intermediate circuit between motor and port pin to drive the motor.

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Would you please explain me How you drive a servo motor by 8051 microcontroller?