NPN transistor is not able to power motor with external 5V power supply

Projects General Guidance
1

Hi all,

I am using a 5V power supply, a NPN transistor, a Arduino and a 3-6 volt motor and my circuit will not work. I have tried many different configurations and they all won’t work. Here is a picture:

image
image1920×1440 303 KB

The red and brown wires extending off the screen go to a 5V battery.

2

A (hand) drawn schematic is a lot clearer to us.

which one ?
what is the value of the resistor. ?
what is the wattage of the motor ?

From the looks of it you have it the wrong way around, but that is just from the looks of it.
Try swapping the yellow & black wires that are connected to the transistor, and please add the flyback diode (cathode to the Green on the motor id' say)

3

Hi,
Can you please post your code?

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Hand drawn and photographed is perfectly acceptable.

What is the transistor you are using?

Do you have a DMM?

Thanks.. Tom... :smiley: :+1: :coffee: :australia:

4

image
image1760×661 148 KB

This is almost completely identical as what I have (after switching the black and yellow wires on my breadboard). The only difference is the batteries equal 4.5 V and not 5V. My transistor is the MPS2222A. TinkerCAD says it should be working, but it isn’t.

Edit: forgot to mention the resistor is 10000 ohms

5

With a 10k base resistor...?? I doubt it too.
Save yourself some grief and use a simple logic level mosfet.

6

Will a ld33v work?

7

The transistor needs at least about 1/20 of the motorcurrent into the base.
Make that 10k resistor about 50x smaller. Try 220 ohm.

It seems connected the wrong way round.
Check the MPS2222A datasheet.
Emitter should be connected to ground.

That diode on the table should be across the motor, to protect the transistor.
Leo..

8

Shows the worth of TinkerCAD.

1 Like
9

Maybe OP used a 2N2222 instead of an MPS2222.
They have a different pinout.
Leo..

10

I think you are using the wrong pin. The pin that you are using is not a PWM pin. Try using pin number 9

11

Also, show us the coding Niko, we might have clues about what is wrong

12

Switch to a 1K resistor first up. (10K should probably also work, but the datasheet mentions 1K)

  • Connect the motor directly to the PSU to verify it still works, and measure the current draw with a DMM
  • Grab another 1K resistor and put it in place of the motor.
  • Instead of driving the transistor from the UNO, connect the resistor at the Base of the transistor to 5v+ of the PSU and see what the voltage reads at the collector to verify that the transistor works.
  • If it still does connect it again to the UNO and see if that still works.

The answer to the problem should become clear to you after this.

1 Like
13

Bullet three will kill the transistor...
The base resistor (other end) should be connected to +.

14

Hi, @niko65

Please draw a schematic, not

Have you checked the E, B, C pinouts of the MPS2222A?

2222pinout
2222pinout530×770 53.1 KB

Thanks.. Tom.. :smiley: :+1: :coffee: :australia:

15

That is what it says.

16

Sorry, you are right...

17

image
image1343×823 116 KB

Sorry this is a very bad drawing. This also could be wrong.

18

NO, do NOT do that.

19

That is a FINE drawing.
But you want something more like:

image
image826×480 1.69 KB

20

Just to be clear, @westfw is referring to the connections, not the appearance or layout.

1 Like