Measuring Standard Cell Voltage

E

Ed Bailen

Guest
Can a modern DVM (10 Meg input) be used to measure the voltage of a
standard cell without damaging the cell?

Regards,
Ed Bailen
 
I would think so.

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"Ed Bailen" <n5kzw@arrl.net> wrote in message
news:rcb8e0tmghablo8v9k9nv0biuf329m7pm0@4ax.com...
Can a modern DVM (10 Meg input) be used to measure the voltage of a
standard cell without damaging the cell?

Regards,
Ed Bailen
Click to expand...
 
Ed Bailen <n5kzw@arrl.net> wrote in
news:rcb8e0tmghablo8v9k9nv0biuf329m7pm0@4ax.com:

Can a modern DVM (10 Meg input) be used to measure the voltage of a
standard cell without damaging the cell?

Regards,
Ed Bailen
Click to expand...
No.(well,you will not -damage- the cell,just alter(screw-up) it's
calibrated voltage)

You need a very hi-Z meter(=/> 100Meg) to avoid disturbing the voltage.
SC's were originally measured using the differential voltage method,using a
adjustable voltage source and a null meter.(At null,impedance is extremely
high,theoretically infinite)

--
Jim Yanik
jyanik-at-kua.net
 
Jim Yanik <jyanik@abuse.gov> wrote in
news:Xns95198305EF2A1jyanikkuanet@204.117.192.21:

Ed Bailen <n5kzw@arrl.net> wrote in
news:rcb8e0tmghablo8v9k9nv0biuf329m7pm0@4ax.com:

Can a modern DVM (10 Meg input) be used to measure the voltage of a
standard cell without damaging the cell?

Regards,
Ed Bailen


No.(well,you will not -damage- the cell,just alter(screw-up) it's
calibrated voltage)

You need a very hi-Z meter(=/> 100Meg) to avoid disturbing the
voltage. SC's were originally measured using the differential voltage
method,using a adjustable voltage source and a null meter.(At
null,impedance is extremely high,theoretically infinite)
Click to expand...
To add;you also will not have enough resolution on a DMM to get an accurate
reading of the SC.

--
Jim Yanik
jyanik-at-kua.net
 
On Thu, 1 Jul 2004 16:53:53 +0000 (UTC), Jim Yanik <jyanik@abuse.gov>
wrote:

Jim Yanik <jyanik@abuse.gov> wrote in
news:Xns95198305EF2A1jyanikkuanet@204.117.192.21:

Ed Bailen <n5kzw@arrl.net> wrote in
news:rcb8e0tmghablo8v9k9nv0biuf329m7pm0@4ax.com:

Can a modern DVM (10 Meg input) be used to measure the voltage of a
standard cell without damaging the cell?

Regards,
Ed Bailen


No.(well,you will not -damage- the cell,just alter(screw-up) it's
calibrated voltage)

You need a very hi-Z meter(=/> 100Meg) to avoid disturbing the
voltage. SC's were originally measured using the differential voltage
method,using a adjustable voltage source and a null meter.(At
null,impedance is extremely high,theoretically infinite)


To add;you also will not have enough resolution on a DMM to get an accurate
reading of the SC.
Click to expand...
Thanks, Jim, I hadn't thought of that.

Ed Bailen
 
"Kevin Carney" <carneyke@us.ibm.combo> wrote in message
news:cc1eus$o4o$1@news.btv.ibm.com...
I would think so.

--
Click to expand...
The small current drawn will greatly affect the accuracy of your
measurement, and probably affect the cell. You should adjust a
precision power supply such as the HP 6111 to the cell voltage, then put
your microvolt meter between the cell and the 6111, and adjust until the
6111 is the same voltage. Then use the 6111 for your measurements. HP
6111 and similar precision PSes go for $40 to $100 on Ebay.


"Ed Bailen" <n5kzw@arrl.net> wrote in message
news:rcb8e0tmghablo8v9k9nv0biuf329m7pm0@4ax.com...
Can a modern DVM (10 Meg input) be used to measure the voltage of a
standard cell without damaging the cell?

Regards,
Ed Bailen
Click to expand...
 
"Ed Bailen" <n5kzw@arrl.net> wrote in message
news:7gole01b3gvcsd935ufqehgu94lqcv71nh@4ax.com...
On Thu, 1 Jul 2004 16:53:53 +0000 (UTC), Jim Yanik <jyanik@abuse.gov
wrote:

Jim Yanik <jyanik@abuse.gov> wrote in
news:Xns95198305EF2A1jyanikkuanet@204.117.192.21:

Ed Bailen <n5kzw@arrl.net> wrote in
news:rcb8e0tmghablo8v9k9nv0biuf329m7pm0@4ax.com:

Can a modern DVM (10 Meg input) be used to measure the voltage of
a
standard cell without damaging the cell?

Regards,
Ed Bailen


No.(well,you will not -damage- the cell,just alter(screw-up) it's
calibrated voltage)

You need a very hi-Z meter(=/> 100Meg) to avoid disturbing the
voltage. SC's were originally measured using the differential
voltage
method,using a adjustable voltage source and a null meter.(At
null,impedance is extremely high,theoretically infinite)


To add;you also will not have enough resolution on a DMM to get an
accurate
reading of the SC.

Thanks, Jim, I hadn't thought of that.
Click to expand...
Depends om the DMM. High end 5-1/2 or 6-1/2 digit meters can measure
microvolts.

http://www.7auction.com/item3826949605-HP%2034401A%206.5%20Digit%20DMM.h
tml



Ed Bailen
Click to expand...
 
"Watson A.Name - \"Watt Sun, the Dark Remover\"" <NOSPAM@dslextreme.com>
wrote in news:10evd2oeptom2a6@corp.supernews.com:

http://www.7auction.com/item3826949605-HP%2034401A%206.5%20Digit%20DMM.h
tml
Click to expand...
I used to have one of these on my workbench at TEK-Orlando.
I don't recall if it has a sufficiently high input-Z.

But a *NICE* DMM.

--
Jim Yanik
jyanik-at-kua.net
 
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