Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: Analog Meters for sale
Posted: Tue Aug 21, 2007 10:09 am
Joined: Mon Apr 10, 2006 12:43 pm
I have the following analog meters for sale. These meters have been in storage for the past couple of years. When they were removed from service they were all working.
Weston Wattmeter Model 432 Quantity of 1 $25.00
Weston Model 264 0 to +/- 50 mA Quantity of 3 $20.00
Weston Model 264 0 to +/- 100 mA Quantity of 1 $20.00
Weston 0 to 150 V AC Quantity of 1 $20.00
Weston 0 to +/- 30 uA Quantity of 1 $20.00
Weston 310 0 to 10V Quantity of 1 $10.00
Western Electric 0 to 1 mA Quantity of 1 $5.00
Knight 0 to 1 mA Quantity of 4 $5.00
Knight 0 to 5 A Quantity of 3 $5.00
Simpson 0 to 50 uA Quantity of 1 $5.00
Simpson 0 to 1 mA Quantity of 6 $5.00
Simpson 0 to 20 mA Quantity of 1 $5.00
Simpson 0 to 100 mA Quantity of 2 $5.00
Simpson 0 to 150 mA Quantity of 2 $5.00
Simpson 0 to 3 A Quantity of 3 (this meter is marked AC) $5.00
Simpson 0 to 5 A Quantity of 3 $5.00
Simpson 0 to 10 A Quantity of 1 $5.00
Triplet 420-G 0 to 1 mA Quantity of 3 $5.00
Triplet 420-G 0 to 1 A Quantity of 1 $5.00
Triplet 420-G 0 to 500 mA Quantity of 5 $5.00
Jewell Electrical Instrument 15V Quantity of 1 $5.00
If anyone is interested I can send a digital picture of the meter. Buyer will pay for shipping.
Post subject: Meters
Posted: Wed Aug 22, 2007 10:03 am
Joined: Tue Dec 26, 2006 5:39 pm
"private messaging is disabled on this board" so I cannot 'pm' you.
send an email to
a l a
s.c o m
There is one on that list I definitely want.
(email address posted in a manner that makes it tough for the spambots to read it.)
I have a 'broken' HP 425A that reads down to +/-10 pA DC full scale.
The HV filter cap went and killed the supply. Sure wish I had a schematic for it.
Back whenever that was made they called it micromicroamperes. The smallest division on the meter is 0.2 pA To read this small of a current it uses a chopper amp. The 'chopper amplifier' is literally a small motor turning a disc with holes in it. #12 lamps on one side and photocells on the other. I wish they had these things in college. When it worked I showed other engineers that if you just grabbed a couple of 'test leads' out of a drawer and 'shorted them' you would read several pA at room temperature and the current would change when I exhaled on the 'shorted' leads. Using a meter that reads that low requires very careful choice of conductors and connectors.