New Here & 1st Problem!

I am going back to my youth as an electronic engineer to design some stuff.

I have joined hoping for help.

This will be the start of a few minor project around building a cockpit for online flying. Basically, Arduino boards loaded with code and game libraries to detect game events. Coding is a new area for me. I’m pre PCs back then

Anyway, my current problem is more descrete.

With Vcc at 5V and Gnd at 0v, why does my LM393N Op Amp output 0.7v when I/P 1(-) is connected to Gnd and I/P 1(+) is 2.5V by connecting to the middle of 2 x 5kOhm in series across Vcc and Gnd???

I was hoping to get 5V O/P to drive a MOSFET Board for a 12v power control over a magnetic field coil…

Top Replies

wolfgangfriedrich 4 days ago

Welcome. You will get answers here. There is a lot of knowledgeable people around.

The LM393 output is an open collector type. You would need a pull-up resistor to Vcc to get a proper high level. Like so (from the TI LM393 datasheet):

And the LM393 is a comparator, not a full op-amp. Just in case you plan to do more analog stuff with it.
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dang74 4 days ago

The LM393N is a comparator and not an op-amp. Also I think it's output is open collector. Try attaching a 10k pull up resistor to its output. See if you get 5V after that change.
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charlieo21 4 days ago

Welcome!
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genebren 4 days ago

Welcome to the element14 community. It looks like you are getting started and already getting some. Good luck with your project and enjoy all that the community offers.
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colporteur 4 days ago

Don't you just hate when someone responds with an alternative and not a reply your question.

I have had great success using this little module to drive 12VDC loads. Do a search for MOSFET driver module on part sites and you should get a hit.

Oh yeah, welcome!
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Gosling616 3 days ago in reply to colporteur

Thanks, I am using this MOSFET board - ￡0.09 37％ Off | 5PCS Top Mosfet Button IRF520 Mosfet Driver Module For Arduino MCU ARM Raspberry Pi 3.3v-5V IRF520 Power MOS PWM Dimming LED
https://a.aliexpress.com/_mqCTYeW

Problem I have is it needs a Vcc to switch on and so I need to convert the Gnd signal the switch gives to a Vcc, hence using the Comparator to Invert the signal.

But thanks anyway…
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Gosling616 3 days ago in reply to genebren

TY. So it seems…
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Gosling616 3 days ago in reply to wolfgangfriedrich

Thanks. Just what I needed - I’ll give that a go and see what happens.
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Gosling616 3 days ago in reply to dang74

Thanks. I’ll try that.
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Gosling616 3 days ago in reply to charlieo21

Thanks. I don’t really know my way around yet and I guess this was the wrong place to post a problem. Can you (or someone) point me to where I should have posted this problem, thanks…
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