1. Home
  2. Electronics Design
  3. FET as linear mode heater
  4. Page 4

FET as linear mode heater

On Monday, May 4, 2015 at 4:09:46 PM UTC-4, Lasse Langwadt Christensen wrot e:

ax current.

5 ohm power resistor in series, with feedback from the resistor to control the current.

n the

ething closer

easier to control.

matter.

l

er,

Yeah sure, (I think the short answer is because I've mostly only read about SMPS.) So to get power control I would change the duty cycle of the buck? What sort of dynamic range can you get?

I was thinking I should make a PWM heater too, with just resistors.

Oh that brings to mind a question. (perhaps simple?) What's the easiest voltage to duty cycle converter. (OK, uC's or some other controller... but after that.)

George H.

Reply to
George Herold
Loading thread data ...

Voltage to duty cycle converter.

George H.

Reply to
George Herold

Sure thing. If the pickup doesn't destroy your measurement, PWM is the way to go.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC 
Optics, Electro-optics, Photonics, Analog Electronics 

160 North State Road #203 
Briarcliff Manor NY 10510 

hobbs at electrooptical dot net 
http://electrooptical.net
Reply to
Phil Hobbs

ore

ve

r

ive

ime

Jim's solution is easy - he understands it the way he wants to understand i t.

He objected to my "emitter-pushing" comment for quite the wrong reason. I'd directed Sylvia Else's attention to the right part of the LM311 integrated circuit, and made a standard get-it-180-degrees-wrong "error-of-action" mi stake in my discussion of what was going to go wrong.

Jim ought to have much clearer insight into what happens inside an LM311 wh en the inputs go outside the design range, but he didn't bother to spell ou t what was actually going on until I'd made a bad attempt at it and he was prompted to correct me.

One of the virtues of sci.electronics.design is that people can post stuff that's not entirely right - Linus Pauling style - and get corrections that that take the discussion to the right conclusion.

--
Bill Sloman, Sydney
Reply to
Bill Sloman

re

e

ve

me

Worrying about the image you present isn't a useful form of intellectual ac tivity. Phil Hobbs does rather more of it than he should.

Winfield Hill long ago perfected the "I'm academically well-informed and th is is how it looks to me" style, but writing and correcting three successiv e editions of his (with Paul Horowitz) text-book has given him a lot of pra ctice on abstracting only the technical points and laying them out clearly.

--
Bill Sloman, Sydney
Reply to
Bill Sloman

If you allow pulse skipping and aren't constrained by frequency, quite a lot.

Resistor, capacitor, and schmidt trigger? Single shot?

Reply to
krw

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.