Is it possible to do what I said in the title? I want to control 2 dc motors using my arduino uno and the shield i have doesn’t work properly. Or so i think and i want to start controling the motors with transistors. I would use a diode but i don’t have one. Could a LED take place if the schematic is modified? Let me know what y’all think 
Then get one if you don't want any problems.
Fine, take a look at this.
http://www.thebox.myzen.co.uk/Workshop/Motors_1.html
and this
http://www.thebox.myzen.co.uk/Workshop/Motors_2.html
1 Like
It looks to me that both links are showing using a diode. The second link I don’t really understand what it talks about
If you don't use the diode, the transistor will be very quickly destroyed. They are extremely cheap, and can be harvested from a PCB from discarded electronics.
See Flyback diodes and why you need them
You will have much better luck with a motor driver, like this one (for small hobby motors).
Yes diodes are essential when dealing with inductive loads.
See this:-
Can you be more specific about what you do not understand?
No modification is required. The LED has to tolerate the motor current.
Most LEDs will not work, because they are not specified to tolerate a reverse voltage equal to the motor voltage, or to tolerate the forward current of the motor.
Buy a diode that can handle the stall current of the motor (check the motor specifications) and typically, 50V reverse voltage. Or just buy a motor driver.
There are a couple of ways;
You could use a capacitor or a series capacitor+resistor. The energy from the motor's inductance (0.5L.I^2) plus the stored kinetic energy can be transferred to a capacitor (0.5C.V^2), a series resistor will aid dissipation of the stored energy and also avoid resonant oscillation.
Some sums involved by you, (not me, LOL too long since I've done anything like this) so that the transistors Vce max is not exceeded.
I suspect that if you do not have a diode to hand then this may be too complicated.
Another alternative is to use a zener, but that is a diode anyway.
There is a reason why diodes are used; low cost, reliable and simple to implement.
Is this because it didn't contain an internal diode and you didn't use any external ones on your motor. Therefore you destroyed your shield for lack of a flyback diode?
This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.