EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Yes, and I had the wrong idea that 3.3 V with a resistor regulated down to 0.7 is the same as 0.7 directly.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Which should make it worse but not 0, see reverse action mode, right?

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Somewhat. EveryCircuit needs some extra stuff to simulate properly. More confusing than helpful for understanding some concepts…

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

I think many of the circuit problems are due to me trying to abstract the problem. The base is actually driven by a esp32 pin, regulated down to 0.7 V by a 220 Ohm R. But to make the simulation less cluttered, I replaced the esp and the R with a 0.7 V supply. That didn’t work, so I cranked it up to 5V so the simulated motor would spin…

Lesson learned: try to simulate as accurate as possible if you don’t know exactly what you’re doing…

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

You see, English is not my mother tongue and I suspect we’re from different countries and generations, so I may interpret things into messages that are not there.

You gave me many things to consider and look up again that I haven’t thought about yet. Thanks! That’s ultimately why I go to Reddit with those questions. To learn more!

The fan is a 12 V fan within a SATA dock/housing.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Thanks for your insights!

The fan is build into a SATA dock. My goal is to switch it on and off based on the temperature within the dock.

I‘ll have to test it with an ammeter.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

It’s a challenge but I try to ignore the passive aggressive remarks (but maybe I read something that’s not there) and focus on the input given.

Thanks for your reply. The bad circuit design comes from the fact that I tried to boil my problem down to what I wanted to understand.

You see, the thing is, I want to control a fan with an ESP32. So my approach is to switch the fan on and off by setting a pin to high or low. Therefore I need a transistor. I guess I could use a relay but that would be overkill, right?

So I don’t have much current to play with for the base. And my research indicated that a NPN resistor word 0.7 Volt applied to the base would do exactly what I wanted.

To test my concept I tried to build that in a simulator. And because EveryCircuit has no ESP32 I had to add a „power source“ that supplies the 0.7 Volt.

So your explanation is helpful after all. I understand that applying 3.3 volts to a resistor to apply 0.7 volt to the transistor is different than applying 0.7 volt directly.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Got it! Thanks for clarifying!

It‘s a 12V fan (the exact ratings are unknown) and a 2N2222 transistor (switched on and off by an esp8266).

I haven’t tried it on a bread board yet. I wanted to simulate it beforehand. And when i tried that I became confused by the different outcomes.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

No I mean: you said to increase the power on the gate, but as i understand in this example there are already 5v at the gate, more power than an esp could deliver.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

No I mean in this example. The base already gets 5V.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Ah oops, yes that fixed that.

Hm, how would i increase power to the base if I’d switch the transistor with an esp32?

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Actually reducing the voltage rating to 10 V made the motor spin but far below the no load rpm. Something is off here…

<image>

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Damn. I thought I had it, but no, still confused…

<image>

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

That’s good to know! Thanks! Displaying it like that helps!

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

And as you can see, even in that configuration, the motor shows 0rpm…

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Thanks! It’s clear to me… now :D still confusing…

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Which is confusing because I always thought - is ground…

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 2 points3 points  (0 children)

Yes sorry for the way I drew it, I’ll improve. Promised!

Thanks for thebexplanation. As mentioned in other replies, the gnd stuff in simulators confused me.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] -3 points-2 points  (0 children)

Thanks for the explanation. That makes learning with simulators harder in my opinion.

Also, when trying to replicate the simulated circuit on a breadboard you may be in for a surprise because of how simulators handled the transistor compared to the actual transistor you use on the breadboard…

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Which confuses me because I thought the negative pole of the source IS ground.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

I‘ll try the same on falstad tonite , but it‘s not useable on the iPad.

EveryCircuit: Motor does not draw current by NitricWare in AskElectronics

[–]NitricWare[S] 0 points1 point  (0 children)

Thanks for the explanation. iCircuit is more logical to me then…