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Cleaning up a voltage

P

Peter

Jan 1, 1970
0
I have a voltage source that alternates between 2v and 7v. I want to
drive a logic level Mosfet with it, so I need the input to be either
0v or 5v. I can limit the high (not really necessary) with a zener,
but what is a SIMPLE way to make the 2v become 0v? I am worried that
the 2v will partially turn on the mosfet and overheat it.
 
C

Costas Vlachos

Jan 1, 1970
0
Peter said:
I have a voltage source that alternates between 2v and 7v. I want to
drive a logic level Mosfet with it, so I need the input to be either
0v or 5v. I can limit the high (not really necessary) with a zener,
but what is a SIMPLE way to make the 2v become 0v? I am worried that
the 2v will partially turn on the mosfet and overheat it.



Do this:

.. 3 x 1N4148
..
.. 2 - 7V o------->|-->|-->|---+-------o 0 - 5V
.. |
.. |
.. .-.
.. | |
.. 10k | |
.. '-'
.. |
.. |
.. ===
.. GND

Regards,
Costas
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J

John Larkin

Jan 1, 1970
0
Do this:

. 3 x 1N4148
.
. 2 - 7V o------->|-->|-->|---+-------o 0 - 5V
. |
. |
. .-.
. | |
. 10k | |
. '-'
. |
. |
. ===
. GND

Regards,
Costas

Right, with maybe a bypass cap across the diodes if mosfet off time is
important.

John
 
P

Peter

Jan 1, 1970
0
Costas Vlachos said:
Do this:

. 3 x 1N4148
.
. 2 - 7V o------->|-->|-->|---+-------o 0 - 5V
. |
. |
. .-.
. | |
. 10k | |
. '-'
. |
. |
. ===
. GND

Regards,
Costas

Thanks for the idea, but will it work with a Mosfet atached to the
output given that the gate is effectively infinite resistance? Will
the diodes still drop the voltage?
 
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