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atz88 • Jul 16, 2008

Mosfet Help

Hey all,

Need some help in working out what is goin on with my mosfet.

Mosfet : IRFB38N20DPBF
200v 44amp N- Channel

Its use: It receives a pulse from the output of my 555 (12-13v) an allows current to flow from the - terminal of a transformer to earth. (also 12-13v)

Problem: Im not getting any pulsing on the Drain Source side.

Troubleshooting: I have hooked it up to battery with the gate through a 50k resistor an without, and with a lamp as the load but stil get the same result which is. The drain- source stays on an eventually fades off, then when i turn the gate on, it does the same, the pulse of the on time is about 1min, where as i need it to be 400hz....

Any help would be greatly appreciated
Check the pulses of 555,and you can set the pulse @400Hz from 555,change the MOSFET and see if the problem still persist.
atz88 • Jul 17, 2008
yep checked the pulse from the 555 to gate at 400hz, an its a new mosfet
how would you set it up in relation to resistors etc, im new to transistors sorry ?
just2rock • Jul 18, 2008
if you have a Mosfet : IRFB38N20DPBF TEST jag then first check the respective MOS for any errors etc.and then later for application onto PLC board.Its 555 application can be monitored with Astable/Bistable /Monostable operations.
Why dont ya replace the mosfet with some other equivalent Mosfet

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