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Simple PWM Flyback driver tutorial

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Step 2: The schematic

Click the left top icon on the image to enlarge it.

Use of the small pushbutton:
Sometimes, the circuit doesn't seem to start up immediately after connecting the power supply to it. When you push this button, it'll start working.
However, I never seem to have this problem any more now.

Note:
Notice that the uper right and upper left connection are the same. We only have to make this connection once.
You can also see in the other pictures that the PWM driver only has 3 connections. +, - and output signal.
The cross in the middle of the schematic is NOT a connection.
 
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miar562 years ago
Will this work using a MTW32N20E mosfet. It's a N channel but seems to have an internal Zener across the source and the gate?
Electorials (author)  miar562 years ago
This mosfet is good.
The diode protects the mosfet, most mosfets have one there.
budhaztm2 years ago
I need some assistence on the mosfet. im pretty confident i wired the two smaller transistors in correctly but im not sure how to wire the big one
Electorials (author)  budhaztm2 years ago
Most MOSFETs will have their connections in this order, from left to right, when holding the front of the MOSFET towards you:
G, D, S

I can't tell you for sure that this will be exactly the same on your mosfet, so you should look up the connections in the datasheet of your mosfet.

If you can't find the datasheet for it, please send me the printed numbers from on your MOSFET and then I'll look it up.
Alex1M62 years ago
Hi what capacitance are those 3.3 "m" capacitors? do you mean nF, uF or mF ?

Thanks.

Electorials (author)  Alex1M62 years ago
it's 3,3nF (nano Farad)


This is printed on the capacitor:

332J
2ASIC

I'm pretty sure that means 3300pF ;)
domints2 years ago
Hi!
I see a bug. You write PNP transistor, but you draw NPN symbol. And as I know this schematics as LED blinker, you just added MOSFET to make more powerfull output and maybe modyfied it a bit, it has to be NPN.

So as conclusion for people, who are new to electronics, you should use NPN, not PNP.
Electorials (author)  domints2 years ago
Oh, Thank you for telling me! I ment NPN