FET driver

Sonnich Jensen · 2015-12-03T08:50:23+00:00

Hi all I was thinking, that for a FET driver I could use a simple op-amp. A FET driver could basically just be 2 transistors supplying enough current to the FET to turn it on immidiately. In my case I and PIC output of a few volts, driving a FET which should run on a 12V system. In this case I could use a FET, set as a comparator, to drive the FET (PIC output to one input and half PIC VDD to the other. This would also offer a level shift, so I can easiler use any FET (not only ones with low VGateOn). The op-amp can also supply the current to turn it on fast. The idea is that an op-amp and 4 resistors are only 5 components, than 6+ transistors and a bunch of resistors (for 2 channels) Does this sound right?

Dec 03, 2015 43 Replies

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Spehro Pefhany 10 years ago

It's been a long time- I *think* around $15-$20 each in smallish quantities.

The spectral response curve is down to 1/10 at 230-255nm depending on the type and most of the 'UV' LEDs are more like 400nm, so no, a malicious element would not be able to fool the flame detector and cause a massive explosion with a UV LED flashlight. These guys

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claim to have UV-C LEDs in the 250-280nm, but that's still well outside of the peak at ~200nm.

The Hammamatsu A type is very insensitive to even the strong Hg line at 253nm.

--sp

Best regards, Spehro Pefhany Amazon link for AoE 3rd Edition: http://tinyurl.com/ntrpwu8 Microchip link for 2015 Masters in Phoenix: http://tinyurl.com/l7g2k48

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M Philbrook 10 years ago

maybe so but, with this output section, its less components and it just fits in.

output section for - RAIL generator.

R1 sets min drive needed.

+------------+ +5 Volt from reg. Vcc(324) | | | | |\+ R1 + -|-\ ___ |< | >--|___|--| PNP -|+/ |\ |/+ | +----+>z-+---+ Vee(324) | | | 5VZ C| --- C| --- C| | | === GND GND (created by AACircuit v1.28.6 beta 04/19/05

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I suppose a charge pump would do but I can't see how to do that using the spare op-amp I had and inserting it into the Vee like I did?

With this, I did not need to have an additional IC body on the board.

Jamie

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Les Cargill 10 years ago

Yes. If the particles form a colloidal suspension in the air, *FOOM* is possible.

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Les Cargill

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George Herold 10 years ago

Thanks, ~$20-40 would be OK, there was one that had a tail out near 300nm. I saw some 308 nm. leds for ~$1. Some sorting and and maybe temperature tuning to change the wavelength?

(Are there other commercial tube photo-cathodes. ) George H.

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