software pwm external source

[raspberry akash]

Hi,
I am using raspberry pi 3 and an external source of 12v to pwm RGB LED strip using transistor PN2222 6E .But when I connect the external source to transistor and LED is remains ON all the time irrespective of the GPIO output connect to base of transistor and emitter grounded and collector with LED. Also I common grounded extrernal source with raspberry pi. Does anyone know what is the problem.

[Jednorozec]

What happens if you connect a single LED in series with a resistor instead of the transistor to the pin that you're using?

[raspberry akash]

What happens if you connect a single LED in series with a resistor instead of the transistor to the pin that you're using?

Then it works fine but I have to control a 12v Led strip hence i am using transistor and an external source

[gordon77]

Have you got a drawing and photo you could show us of what you have wired ?

[raspberry akash]

What happens if you connect a single LED in series with a resistor instead of the transistor to the pin that you're using?

Then it works fine but I have to control a 12v Led strip hence i am using transistor and an external source

Ahh my bad...without transistor it works fine but with transistor its always ONN

[raspberry akash]

Have you got a drawing and photo you could show us of what you have wired ?

https://www.google.es/imgres?imgurl=htt ... mrc&uact=8

[Jednorozec]

That is what you are copying from, not what you have wired. If you're using bipolar transistors instead of MOSFETs, the pinout is totally different and you need a resistor in series with the base.

[raspberry akash]

That is what you are copying from, not what you have wired. If you're using bipolar transistors instead of MOSFETs, the pinout is totally different and you need a resistor in series with the base.

Now with Mosfet its working but the PWM is not accurate. I know one leg is missing thats why I am asking in the forum otherwise I wouldnt have asked in the first place

[Heater]

"One leg is missing"

What?

Without an accurate circuit diagram, including part numbers, of what you have actually constructed nobody can help you. Or perhaps a clear photo.