Thanks for the reply JYelton, Below is the requested diagram of my circuit.


simulate this circuit – Schematic created using CircuitLab

How to short a DC motor?

I was trying to short motor with the help of the circuit given in the above link.

My circuit specification are

  • Motor=9V dc motor,115mA(max)
  • Diode and capacitor across motor
  • Q1=2N4401,hfe(typical=200)
  • Q2=2N4401,hfe(typical=200)
  • Q3=2N4403,hfe(typical=200)
  • Supply for Q1 and Q2 is from Arduino=5V,
  • R1=1.68k
  • R2=10k
  • R3=100ohm
  • R4=100ohm
  • (Base resistor for Q2)

ISSUE: Motor takes off rather than stopping after the required time. The brake time given is 50msec soon after the transistor Q1 is turned off. Is it the base resistor R1 and R4 that causing the problem or the transistors?

Kindly please advice what's wrong in the circuit design?

  • 2
    \$\begingroup\$ Can you include a schematic please? (There's a schematic button just above the editor.) \$\endgroup\$ – JYelton Mar 17 '14 at 20:21

The schematic in the link is for powering a motor, not shorting it out (as per what you'd do when designing an active brake). Look at the bottom of this link to see how they do it using a H bridge. This is the link that is also covered in the question in your link: -

enter image description here

  • \$\begingroup\$ Thanks for the reply sir. Im trying to design a unidirectional motor control circuit. I have uploaded my circuit. \$\endgroup\$ – B1980 Mar 18 '14 at 1:41

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