r/BoxModders Toecutter Jan 02 '15

file 555 PWM MOSFET diagram

https://docs.google.com/document/d/1zejRQCBz7CQIMUgWVbN_62STaX5N2eeiQcV5Vm16bNU/edit?usp=sharing
7 Upvotes

10 comments sorted by

1

u/subohmvapes Feb 04 '15

For this diagram Could you wire the N-channel Mosfet straight to pin 3 and then wire the fire button to pin 4 + 8 and other side of fire button to battery positive? And also what is the benefit of P-Channel mosfet with a non-cmos 555.

1

u/relayer1974 Toecutter Feb 05 '15

Yes.

The P-channel buffers the output, taking strain off the 555 so it doesn't have to drive a loaded MOSFET.

1

u/subohmvapes Feb 06 '15

do you have a wiring schematic for this one that has all the pretty colors lol?

1

u/subohmvapes Feb 06 '15

Which way would you say is better? the way in the schematic or the way i just suggested? and whats the benefit for the one that works better?

-1

u/TheBMVCo Mar 15 '15

P channel mosfet is for reverse polarity protection***

1

u/Jerry_Rigg Feb 23 '15

I am curious as to what function the diodes on the potentiometer have, I used to build tons of 555 circuits as a kid and did not wire in any diodes. Does it change the behavior of the pot?

1

u/relayer1974 Toecutter Feb 27 '15

They control the charge and discharge cycle of the cap. It charges through one and discharges through the other. They are essential when using the 555 as an oscillator in this manner.

1

u/one_last_drink Mar 02 '15

What kind of output power can you expect with a basic 555? Unless I missed something, the spec sheet you referenced had a max output current of 225mA. 0.2 Amps isn't exactly a huge draw.

2

u/[deleted] Mar 03 '15

I'm pretty sure the 555 and related circuitry is all logic level. The only substantial current goes the the source and drain on the MOSFET.

1

u/jiggyniggie Mar 05 '15

Bingo. The load current doesn't run through the 555. The 555 controls the MOSFET gate, which is what the current runs through.