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Circuit help with Wemos D1 Mini

PostPosted: Sun Aug 16, 2020 6:16 am
by Rob Gnarly
Hiya I have recently entered the world of microcontrollers.
I have put together a circuit to turn up and down an LED's brightness with OSC -> PWM and it works well.
Next I added a passive RC filter and had things still working fine. Finally I attempted to step my 0 - 3.3 voltage up to 0 - 5v using a TL072Cp op amp, and I've run into some issues. I'm powering the op amp from the 5v pin but the same issue seems to be present when I use an external 5v supply. Basically the LED remains on and unchanging. I tested the circuit before the op amp and the values seem to be changing fine still with OSC so is something to do with op amp, I tested with another of the same op amp but same issue, here is my badly drawn schematic, if anyone could please help me understand what I'm doing wrong that'd be greatly appreciated! :D

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Re: Circuit help with Wemos D1 Mini

PostPosted: Mon Oct 05, 2020 6:18 am
by bobby hamus
Rob Gnarly wrote:Hiya I have recently entered the world of microcontrollers.
I have put together a circuit to turn up and down an LED's brightness with OSC -> PWM and it works well.
Next I added a passive RC filter and had things still working fine. Finally I attempted to step my 0 - 3.3 voltage up to 0 - 5v using a TL072Cp op amp, and I've run into some issues. I'm powering the op amp from the 5v pin but the same issue seems to be present when I use an external 5v supply. Basically the LED remains on and unchanging. I tested the circuit before the op amp and the values seem to be changing fine still with OSC so is something to do with op amp, I tested with another of the same op amp but same issue, here is my badly drawn schematic, if anyone could please help me understand what I'm doing wrong that'd be greatly appreciated! :D

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Any Update on this OP?

Re: Circuit help with Wemos D1 Mini

PostPosted: Tue Oct 06, 2020 3:59 am
by QuickFix
Have you tried using a MOSFET instead?
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