Simple DC motor control doesn't work without LED

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suwaii

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hi
i try to make the simple DC motor control by trsnasistir but the motor will not work but if i put the LED in place of the DC motor the circuit will work and the LED will flash

in the attachment is the circuit can you tell me what is the mistake in the circuit
 

Re: simple DC motor control

What is the voltage of the motor? check it and try to run the motor directly for test it
 

Re: simple DC motor control

exactly i do not know but if you connect the motor direct with 5V it will work even i try to use 10V in the circuit but the motor does not work
 

simple DC motor control

What current does the motor take at 5V?

Keith.
 

simple DC motor control

check also the width of the pulses - if they are to narrow, the motor will be unable to start to spin.
 

simple DC motor control - help needed

Hi,
You can connect the base resistor direct to + 5V for check if the transistor is dead or functions (but with the motor as load)...
K.
 

Re: simple DC motor control - help needed

Hi,

check the voltage across the motor using DVM when it is running mode.

Hope that you made the circuit as below



I checked it and did not notice any problems

regards
bassa
 

simple DC motor control - help needed

Since you are PWMing this you should add a freewheel diode. If you only want on off control you need to add some circuitry to clamp the collector voltage. Otherwise at turn off the collector voltage will increase until the transistor breaks down.
 

Re: simple DC motor control - help needed

You should try looking for an H-bridge circuit, this is "de rigeur" for DC motor drive.
 

Re: simple DC motor control - help needed

Thanks for all

i think i find the reasons .. the voltage of the base of transistor should be less than
voltage of that connect to DC moto to transistor i make the voltage of base= 1.5V with series with resistance 100 then the DC motor will work.Howver , if the base voltage same as voltage of DC motor that connect to collector of trnasistor then the DC motor will not work
 

Re: simple DC motor control - help needed

Hi

1. I think you can use 5 volt as a trigger to the base of the transistor but then use a much bigger ressistor to lower the voltage that acctually lies on the base. (eventually it is current activated anyway)
2. dont forget the flywheel diode otherwise the transistor might born.
you can see of how to put the diode: **broken link removed**

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