I need to buy or create a circuit to amplify a 3.3v PWM signal to a 5V PWM signal. I tried creating one based on a simple motor drive circuit, but it didn't work. The PWM signal was lower than the base pin.
I'm using a BC547 transistor and a 100 ohm resistor between 3.3v signal and base.
What does this mean? That circuit should be fine.
What is the actual load on the output?
If it is a motor, what is the stall current?
A BC547 is a small-signal transistor, with an absolute max collector current of 100mA.
Not suitable for motors larger than a pea.
A 2N2222 or BC337 could be a better choice.
A 100 ohm base resistor draws (3.3 - 0.7) / 100 = 26mA from a 3.3volt pin.
Which 3.3volt processor can safely deliver that?
Leo..
I think you win!
That was seriously funny. 
You are sure you have the transistor pinout correct?
Ron
Or a SQUIGGLE motor, 1.8 x 1.8 x 6 mm.
Hi, @andrew_mandrona
Welcome to the forum.
Can you please post some images of your project?
So we can see your component layout.
What did you use for the 5V power supply?
What is the load that needs the 5V PWM?
How did you gather this?
Do you have a scope?
Do you have a DMM? Digital MultiMeter.
Thanks.. Tom.. 
Bet you did this, beginner's amp, common collector (emitter follower).
The "load" is an analog input on another device, so load is close to zero. I'm trying to change a 0-3.3v output from a processor to a 0-5v input that is expected by the receiving device.
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