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Glenn Ashmore
Guest
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 Posted:
Mon Feb 14, 2005 10:59 pm Post subject:
Voltage doubling? |
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I have a 1000 PSI pressure transducer that outputs a 0 - 5VDC signal. I
want to double the voltage to display the pressure on a cheapo LCD panel
meter that reads 0 - 20V. How can I change the signal so that it reads
correctly on the meter? i.e. 800PSI = 4V in = 8V out.
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com
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John Fields
Guest
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| Posted:
Mon Feb 14, 2005 11:39 pm Post subject:
Re: Voltage doubling? |
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On Mon, 14 Feb 2005 11:59:04 -0500, "Glenn Ashmore" <gashmore@cox.net>
wrote:
| Quote: | I have a 1000 PSI pressure transducer that outputs a 0 - 5VDC signal. I
want to double the voltage to display the pressure on a cheapo LCD panel
meter that reads 0 - 20V. How can I change the signal so that it reads
correctly on the meter? i.e. 800PSI = 4V in = 8V out.
|
0-5V>------|+\
| >---+--->0-10V
+--|-/ |
| |
+---[R]---+
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[R]
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GND
R can be anything as long as they're both the same and the opamp can
supply the drive current. 100k would probably be fine, but I'd go
with 10k if I could. If you get an opamp with rail-to-rail inputs and
outputs you'll be able to use a single 12V supply, otherwise you'll
need a positive supply high enough to give the opamp the headroom it
needs to get the output to +10V and a negative supply low enough to
keep the output from bottoming out before the input gets to zero
volts.
--
John Fields |
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Clarence_A
Guest
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| Posted:
Tue Feb 15, 2005 6:10 am Post subject:
Re: Voltage doubling? |
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"Glenn Ashmore" <gashmore@cox.net> wrote in message
news:oN4Qd.41657$EG1.4052@lakeread04...
| Quote: | I have a 1000 PSI pressure transducer that outputs a 0 - 5VDC
signal. I
want to double the voltage to display the pressure on a cheapo
LCD panel
meter that reads 0 - 20V. How can I change the signal so that
it reads
correctly on the meter? i.e. 800PSI = 4V in = 8V out.
--
Glenn Ashmore
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Simple Operational Amplifier? Works for me!
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Rich Grise
Guest
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| Posted:
Wed Feb 16, 2005 6:10 am Post subject:
Re: Voltage doubling? |
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On Mon, 14 Feb 2005 11:59:04 -0500, Glenn Ashmore wrote:
| Quote: | I have a 1000 PSI pressure transducer that outputs a 0 - 5VDC signal. I
want to double the voltage to display the pressure on a cheapo LCD panel
meter that reads 0 - 20V. How can I change the signal so that it reads
correctly on the meter? i.e. 800PSI = 4V in = 8V out.
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Most cheapo panel meters I've seen actually have an input voltage of 0-.2
V, and you scale it with input resistors. For example, to display 0-2V,
you'd use an input divider of 900K/100K for an input of 1M, and a division
factor of 10. So, if you want it to display 10 when the input is 5, you
need to divide 5V down to 100 mV. That's assuming 200 mV full-scale.
If your panel meter really really really expects 20V at its input, you
have a whole nother project on your hands.
But seriously, look for input range jumpers or something of that nature.
It's probably as simple as selecting a resistor.
And the decimal point is usually as simple as grounding one tie point. :-)
Good Luck!
Rich |
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