Really Simple Transistor Circuit Woes

[Cupcakus]

I'm trying to build a very simple transistor circuit to turn on a 12v 5w bulb when a 5v signal is introduced. It's wired like this

+12v->Bulb->Collector
Emitter->Ground

When I apply +5v to base, the transistor explodes... literally... this led me to think the transistor wasn't rated for the load, but it seems to be unless I'm reading the data sheet wrong. It should be rated up to 3A, I'm only using about 0.42A

i've attached the datasheet for the transistor in question.

What am I doing wrong here? Any help would be appreciated.

 

[KJ6EAD]

Excess base current? Add some resistance between that 5V and the base to get the current down to about 50mA.

 

[Cupcakus]

Excess base current? Add some resistance between that 5V and the base to get the current down to about 50mA.

What would the 5v current be in this application? Same as the 12v current? Trying to determine how large a transistor to put in there...

 

[keith1200rs]

Minimum current gain is 20 at room temperature so maybe make base current 1/15 of collector current so 28mA. You lose around 0.7V on the base-emitter so have 4.3V left. Around 150 ohms will give 28mA.

Keith

 

[jeffttan]

current gain is at 10... if you want a current of 0.41 amps on the bulb, you might want to put a 100 ohm resistor at the base.

 

[ashokok]

When I apply +5v to base, the transistor explodes... literally... this led me to think the transistor wasn't rated for the load, but it seems to be unless I'm reading the data sheet wrong. It should be rated up to 3A, I'm only using about 0.42A

yes you required Base resistor to control collector current.
i think your using the Bulb is filament type the initial current will 15 times higher than rated current (0.42A)


P.Ashok Kumar

 

[Audioguru]

Post a video of the transistor blowing up because you forgot to limit the base current.
Don't you know how a transistor works?????

 

[mrjava241]

Missing base R? If you can't have a base resistor, use a FET instead but make sure you have a drain resistor in that setup. 12V+->Bulb->Drain R->FET->Ground.