Guest
Let me guess... it's NOT normal for a mosfet to register < 40 ohms
between D and S with no gate voltage applied...
correct?
Michael
between D and S with no gate voltage applied...
correct?
Michael
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J
Jon Slaughter
Guest
<mrdarrett@gmail.com> wrote in message
news:af6d3ad2-7e4a-44f3-8691-04437b5d905f@m3g2000hsc.googlegroups.com...
news:af6d3ad2-7e4a-44f3-8691-04437b5d905f@m3g2000hsc.googlegroups.com...
If the gate is floating it might? Or if it's depletion mode?Let me guess... it's NOT normal for a mosfet to register < 40 ohms
between D and S with no gate voltage applied...
correct?
J
John Fields
Guest
On Fri, 10 Oct 2008 09:44:44 -0700 (PDT), mrdarrett@gmail.com wrote:
Remember that the gate is completely isolated from both the drain and
the source by the gate oxide, so if the charge isn't drained the MOSFET
will stay on for quite some time after you disconnect the gate from the
12V supply.
JF
---On Oct 10, 9:37 am, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
mrdarr...@gmail.com> wrote in message
news:af6d3ad2-7e4a-44f3-8691-04437b5d905f@m3g2000hsc.googlegroups.com...
Let me guess... it's NOT normal for a mosfet to register < 40 ohms
between D and S with no gate voltage applied...
correct?
If the gate is floating it might? Or if it's depletion mode?
I've got IRF530 and an IRLZ34N mosfets.
I noticed something was up when my power supply's current limiting
circuitry deactivated the power supply.
Debugging: one at a time, I connected the drain to a 12V light bulb,
and tapped the gate with +12V. The light bulb turned on, and STAYED
on even with the gate voltage removed. That's not supposed to happen,
is it?
Remember that the gate is completely isolated from both the drain and
the source by the gate oxide, so if the charge isn't drained the MOSFET
will stay on for quite some time after you disconnect the gate from the
12V supply.
JF
E
Eeyore
Guest
mrdarrett@gmail.com wrote:
Now try SHORTING the gate to the source.
Graham
Applied ? Sure there's not some charge on there already.Let me guess... it's NOT normal for a mosfet to register < 40 ohms
between D and S with no gate voltage applied...
Now try SHORTING the gate to the source.
Graham
Guest
On Oct 10, 9:37 am, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
I've got IRF530 and an IRLZ34N mosfets.
I noticed something was up when my power supply's current limiting
circuitry deactivated the power supply.
Debugging: one at a time, I connected the drain to a 12V light bulb,
and tapped the gate with +12V. The light bulb turned on, and STAYED
on even with the gate voltage removed. That's not supposed to happen,
is it?
At first I thought I had a bum IRF530, burned out from previous
experiments, so I tried my IRLZ34... same thing...
A TIP31A behaves as I'd expect it to though... turns on, then off when
I remove voltage from the base...
Transistor triage...
Michael
mrdarr...@gmail.com> wrote in message
news:af6d3ad2-7e4a-44f3-8691-04437b5d905f@m3g2000hsc.googlegroups.com...
Let me guess... it's NOT normal for a mosfet to register < 40 ohms
between D and S with no gate voltage applied...
correct?
If the gate is floating it might? Or if it's depletion mode?
I've got IRF530 and an IRLZ34N mosfets.
I noticed something was up when my power supply's current limiting
circuitry deactivated the power supply.
Debugging: one at a time, I connected the drain to a 12V light bulb,
and tapped the gate with +12V. The light bulb turned on, and STAYED
on even with the gate voltage removed. That's not supposed to happen,
is it?
At first I thought I had a bum IRF530, burned out from previous
experiments, so I tried my IRLZ34... same thing...
A TIP31A behaves as I'd expect it to though... turns on, then off when
I remove voltage from the base...
Transistor triage...
Michael
E
Eeyore
Guest
mrdarrett@gmail.com wrote:
Graham
Will post to the original thread.Eeyore wrote:
mrdarr...@gmail.com wrote:
Let me guess... it's NOT normal for a mosfet to register < 40 ohms
between D and S with no gate voltage applied...
Applied ? Sure there's not some charge on there already.
Now try SHORTING the gate to the source.
Ok, will do when I get home from work.
Mosfets in critical but stable condition...
How's the girl from the pub doing?
Graham
Guest
On Oct 10, 10:47 am, John Fields <jfie...@austininstruments.com>
wrote:
Oh ok! I'll breadboard a test circuit that grounds the gate, and see
if that fixes things...
Thanks,
M
wrote:
On Fri, 10 Oct 2008 09:44:44 -0700 (PDT), mrdarr...@gmail.com wrote:
On Oct 10, 9:37 am, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:
mrdarr...@gmail.com> wrote in message
news:af6d3ad2-7e4a-44f3-8691-04437b5d905f@m3g2000hsc.googlegroups.com...
Let me guess... it's NOT normal for a mosfet to register < 40 ohms
between D and S with no gate voltage applied...
correct?
If the gate is floating it might? Or if it's depletion mode?
I've got IRF530 and an IRLZ34N mosfets.
I noticed something was up when my power supply's current limiting
circuitry deactivated the power supply.
Debugging: one at a time, I connected the drain to a 12V light bulb,
and tapped the gate with +12V. The light bulb turned on, and STAYED
on even with the gate voltage removed. That's not supposed to happen,
is it?
---
Remember that the gate is completely isolated from both the drain and
the source by the gate oxide, so if the charge isn't drained the MOSFET
will stay on for quite some time after you disconnect the gate from the
12V supply.
JF
Oh ok! I'll breadboard a test circuit that grounds the gate, and see
if that fixes things...
Thanks,
M
Guest
On Oct 10, 11:00 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
Ok, will do when I get home from work.
Mosfets in critical but stable condition...
How's the girl from the pub doing?
Thanks,
M
wrote:
mrdarr...@gmail.com wrote:
Let me guess... it's NOT normal for a mosfet to register < 40 ohms
between D and S with no gate voltage applied...
Applied ? Sure there's not some charge on there already.
Now try SHORTING the gate to the source.
Graham
Ok, will do when I get home from work.
Mosfets in critical but stable condition...
How's the girl from the pub doing?
Thanks,
M