General > General Technical Chat
50G ohm Retirement Fund
TheSteve:
There does seem to some interest - why not list them for sale in the buy/sell section. Sell them in lots of 50 or 100 or something.
Tom45:
--- Quote from: alm on March 15, 2017, 09:43:19 am ---Well, 50 GOhm resistors do exist in 0805 (up to 100 GOhm in that series). Make sure you do not exceed that 1/8 W power rating ;).
--- End quote ---
:-DD 79 KV is needed to hit 1/8 W power dissipation. I wonder why they even bother with a maximum power specification for these.
Red Squirrel:
How do they react to heat, I wonder if they are more meant for less conventional use of resistors such as very sensitive sensory applications?
Cerebus:
--- Quote from: Red Squirrel on March 15, 2017, 07:40:09 pm ---How do they react to heat, I wonder if they are more meant for less conventional use of resistors such as very sensitive sensory applications?
--- End quote ---
Usually terribly. Typical tempco for this kind of resistor is in the 1000ppm region, worse than won-hung-lo SMD resistors in more 'normal' values at typically 100 - 200ppm. Note the 30% tolerance. These get used in the kind of instruments that you calibrate before every reading and take the reading quickly before the instrument drifts too much. It's no accident that picoammeters come with accuracies on the order of 0.3% when comparable voltmeters have accuracies 100 times better.
ocw:
I just received four TE Connectivity RH73X2A50GNTN 50G ohm 30% 0805 resistors which were ordered from Mouser. Attached is a picture of them. I don't know how many other 50G 30% 0805 resistors are being made, but the pictured large bag does not contain TE's version. I included an Ohmite MOX-1125-23-4008J 40G resistor for a size comparison.
I measured the four resistors as 37.1G (-25.8%), 38.0G (-24%), 45.8G (-8.4%) and 54.9G (+9.8%). Those measurements were made using my Keithley 610C electrometer. I'll probably later measure their values using my homemade meter using a ADA4530-1. The capacitance of the resistors were measured to be about 0.61 pF for each of them.
I'd recommend checking the capacitance of those components in the bag. I suspect that they will measure significantly above 1 pF and that you have ceramic capacitors which have a leakage around 50G ohm. You will need to find another source for your retirement fund.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version