Dc motor

Thread Starter

Berzin

Joined Dec 17, 2020
59
Hi guys today actually I was trying to use a 12 volts dc motor with the help of transistor bc547 and 12 volts relay to trigger it but i dont know why but my motor is is not getting triggered by any means but only when I attach the 9 volts battery to that time it work so this shows my motor is not bad please can any help me
 

Papabravo

Joined Feb 24, 2006
16,118
Transistors don't work that way. See the textbook on this site or consult an alternate source for information on how to use a transistor as a switch.
Your diagram does not label the transistor connections. For all we know you may have wired it backwards.
 

KeithWalker

Joined Jul 10, 2017
1,780
Can you rephrase that please.
The motor will be either switched on or off when the input resistor is connected to a positive source, depending on whether you wire the motor to the normally open or normally closed contacts of the relay.
If you really connected the transistor the way you show in your first diagram, with the base connected directly to the positive supply, it will no longer be a transistor. It will now be a lump of epoxy with three wires sticking out of it. The base current needs to be limited to a safe value with a resistor. See the maximum ratings in the data sheet for that transistor.
 

MrChips

Joined Oct 2, 2009
23,519
I don't understand your question.
Digital control signals from a computer might look like this.

1612712152222.png

As you can see there are three stages, a leading level, an active level, and a trailing or idle level.
What state do you want the motor to be in (run or off) at each stage?

There are other means of control, for example, leading edge and trailing edge. And there are more. But let's leave these out for the time being.
 

Audioguru again

Joined Oct 21, 2019
3,177
You have burned out the base-emitter diode of the transistor since you connected its base to +12V without using a series current-limiting resistor. You correctly show the top view of a BC547 and its base as its center pin.
The datasheet for the BC547 shows that its maximum allowed collector current is only 100mA but since you did not say the current or resistance of the relay coil we co not know if the BC547 is suitable.
 

Thread Starter

Berzin

Joined Dec 17, 2020
59
What is ic LTC3863 used for and does it really converts positive inputs to negative output and can there be any alternative for this which is available easily
 
Last edited:

MrChips

Joined Oct 2, 2009
23,519
Simple. Force the electrons to turn around and move in the opposite direction.
:)
You can also do this by reversing the connections to your motor with a double-pole double-throw switch.
You can also do it with an H-bridge. Seriously.
 
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