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npn sensor wiring with lm7805 ??

Posted by Nikki81

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Nikki81

npn sensor wiring with lm7805 ??
February 09, 2017 11:01AM

Registered: 9 years ago
Posts: 198

I want to wire a npn sensor with a lm7805. Will this work or will i just end up with the blue smoke ?

thanks Nikki

IMG_2044.JPG

Edited 1 time(s). Last edit at 02/09/2017 11:02AM by Nikki81.

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o_lampe

Re: npn sensor wiring with lm7805 ??
February 09, 2017 11:31AM

Registered: 8 years ago
Posts: 5,232

The 7805 can cause some latency or bouncing. something you don't want to see in a probe-signal. Why not use a resistor divider?

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obewan

Re: npn sensor wiring with lm7805 ??
February 09, 2017 12:01PM

Registered: 7 years ago
Posts: 759

You will get some nice smoke if you connect the blue and black together
connect brown to +12v
connect black to i/p of regulator.

but as o_lamp said , a resistive divider has 0 latency.

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Nikki81

Re: npn sensor wiring with lm7805 ??
February 09, 2017 02:50PM

Registered: 9 years ago
Posts: 198

Thanks Ill use a resistor divider i just had a few lm7805s to hand

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Nikki81

Re: npn sensor wiring with lm7805 ??
February 10, 2017 11:01AM

Registered: 9 years ago
Posts: 198

Is this the correct wiring for a npn sensor ?

IMG_2046.JPG

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obewan

Re: npn sensor wiring with lm7805 ??
February 10, 2017 03:53PM

Registered: 7 years ago
Posts: 759

more like this
Dont forget to disable Z pullup on this pin

e285a65717.jpg

Edited 1 time(s). Last edit at 02/10/2017 03:54PM by obewan.

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Nikki81

Re: npn sensor wiring with lm7805 ??
February 11, 2017 03:03AM

Registered: 9 years ago
Posts: 198

fantastic i'll get it wired up later on.

Thanks Nikki

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Nikki81

Re: npn sensor wiring with lm7805 ??
February 11, 2017 09:45AM

Registered: 9 years ago
Posts: 198

I have followed your diagram but i am having some problems.

powered up with 12v not activated showing 0.29v

IMG_2049.JPG

activated showing 2.69v

IMG_2050.JPG

IMG_2051.JPG

IMG_20521.JPG

Edited 1 time(s). Last edit at 02/11/2017 09:49AM by Nikki81.

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obewan

Re: npn sensor wiring with lm7805 ??
February 11, 2017 10:37AM

Registered: 7 years ago
Posts: 759

Try with a 33k ohm and a 22k ohm. the others may be loading the probes internal diodes.