On Mar 1, 5:09 pm, Robert Baer wrote:
David L. Jones wrote:
On Mar 1, 12:27 pm, "Too_Many_Tools" wrote:

I have a well stocked test bench at home containing a range of analog,
digital and RF test equipment as I am sure most of you also do.

Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?

Links to recommended circuits, pictures and sources would be
appreciated.

Since this is a need for anyone who has test equipment, I hope to see
a good discussion on this subject.

If you've got that sort of gear at home then usually you have better
(and calibrated) gear at work as well, in which case most of us would
simply bring in our gear from home and spot check it against the good
gear.

In the absense of this gear, you can simply use precision components.
Voltage reference chips with 0.05% or better are cheap and readilly
available.
0.01% resistors are available too.

If you have multiple meters for example, you can also keep an eye on
them by comparison. Using any old component, if all three meters read
the same then you can be pretty confident they haven't drifted.

Checking scope horizontal timebases is easy with a crystal oscillator
and divider.

There are various methods for getting an accurate frequency standard,
but one of the newst methods is using a GPS derived reference. Second
hand Rubidium standards can also be had on eBay.

Generally though, good quality test gear does not drift out of spec,
so the need for regular calibration is minimal.

Dave

True, 0.01% resistors are available, *but* they are extremely
expensive (over $100 each) and they are made when and if the
manufacturer sees fit to do so.

Not so.
RS Components have 0.01% resistors for AU$34.50 (US$26)
Farnell have 0.02% for as little as AU$20

Dave