With the load on the source, and 6-7 volts measured there, the gate
is reverse biased (negative) relative to the source.  That won't
turn it on...  The load should be on the drain.  Then when on, the
gate will be 5v *higher* than the source.

On Wed, 8 Dec 1999 20:27:31 -0500, Fansler, David wrote:

>I am working on a project that uses a PIC to operate 3 logic level HEXFET's
>(IRLIZ44N & IRLD014) that is driving me crazy.  I was under the impression
>that logic level HEXFET's would (when +5V is applied to the gate) would open
>up an pass whatever voltage was on the drain to the source (within the
>limits of the device).  Ain't happening.  All I get is 6 - 7 v through the
>device, with 24vdc on the drain.  And yes, I do have the gate, drain, source
>pins correctly identified.  I have tried high side, low side and would try
>third side if I knew how.
>
>Basic circuit is
>                +24vdc
>              |
>                Drain
> +5V------Gate
>                Source
>              |
>           24 vdc relay coil
>              |
>             GND
>
>To date I have not even put the PIC in the circuit, but rather just fed 5v
>from the power supply.
>Any ideas or help would be greatly appreciated - I am beginning to doubt my
>manhood!
>Thanks
>David
>