Transistor exhibiting weird behavior

Thread Starter

Man10

Joined Jul 31, 2018
163
I have a tip36C transistor. If i connect the emitter to the positive terminal of a 3 volt battery and the collector to the negative terminal of the battery and the base is not connected to anything, it will turn on a motor. And If i connect the emitter to the negative terminal of a 3 volt battery and the collector to the positive terminal of the battery and the base is not connected to anything, it will turn on a motor. Why is it doing that?
 

dl324

Joined Mar 30, 2015
16,988
Why is it doing that?
It shouldn't do that. That transistor has a 100V Vceo and shouldn't conduct significant current at 3V. At 100V, it could conduct 30mA.

You should post schematics when discussing circuits. I've never used TIP36 and needed to download the datasheet to find it's polarity.
 
Last edited:

dl324

Joined Mar 30, 2015
16,988
What is Vceo?
Vceo is the collector-emitter breakdown voltage with the base open.

I was editing my post while you were responding. I corrected the breakdown voltage (I gave the voltage for the A suffix) and added the breakdown current.
 

Thread Starter

Man10

Joined Jul 31, 2018
163
Where is the motor connected?
1 pin is connected to 1 end of the motor and the other end of the motor is connected to the negative terminal of the battery and another pin is connected to the positive terminal of the battery. The base is not connected to anything. Sometimes emtter is connected to positive terminal and collector is connected to motor. Sometimes collector is connected to positive terminal and emitter is connected to motor. Either way motor turns on. Sometimes motor is RE-140RA. Sometimes motor is Mabuchi 555.
 

dl324

Joined Mar 30, 2015
16,988
1 pin is connected to 1 end of the motor and the other end of the motor is connected to the negative terminal of the battery and another pin is connected to the positive terminal of the battery.
This isn't what you said in your original post, but I assumed you plan to control the motor with the transistor and wouldn't have connected the motor in parallel with the transistor.

A wiring diagram/schematic would eliminate confusion.
 

dl324

Joined Mar 30, 2015
16,988
It's connected in series with the battery.
But that isn't what you said in your first post.
If i connect the emitter to the positive terminal of a 3 volt battery and the collector to the negative terminal of the battery and the base is not connected to anything, it will turn on a motor. And If i connect the emitter to the negative terminal of a 3 volt battery and the collector to the positive terminal of the battery and the base is not connected to anything, it will turn on a motor.
Which illustrates my point that a schematic would be better than words because you weren't able to describe what you meant.
 
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