Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

variable regulator with mosfet

Status
Not open for further replies.
6

6v6audio

Newbie level 4
Joined
Nov 14, 2005
Messages
5
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,319
Hi,

I have a tube circuit with a B+ of about 300volts. I want to control the B+ with a mosfet, like the irf350. put a pot on the gate to control the B+.

Can anyone help me or poiunt me to a similar circuit or a forum where this is more appropriate?

Thanks
 

Try this circuit .. T2 and R2 limit the output current and can be removed ..
Regards,
IanP
 
thats 100ma. I need more current.

Whats the zener doing? diff voltage?
 

As I mentioned before, if you remove T2 and R2 there will be no current limit, or if you want to keep it calculate R2 as follows --> R2=0.7V/Iout ..
BUZ326 ( http://home.planet.nl/~midde639/specs/buz326.pdf ) is 10A mosfet and you can always select different one, parallel two or more etc. etc.
Also, you may need to increase capacitance C1 (≈1000µF per 1A of output current) ..
Regards,
IanP


Zener diode limits Ugs to max 12V thus protects the gate of the MOSFET ..
 

Sorry for this stupid question but what is Ugs?
 

I'll also have to change T2, it is rated at 100ma.
 

T2 as part of the current limiting circuit will never conduct much current as if current limit conditions occure the whole T2s current will come from 560kΩ resistor .. so BC547 is just fine ..
Regards,
IanP
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top