- blaupunkt tv gives no picture - 1 Update
- Resistor colours - 3 Updates
- what is a noisy resistor anyway/ - 6 Updates
| alanbiggrif74@gmail.com: Dec 13 05:12AM -0800 My blaupunk tv is coming on but no picture just has the blaupunk on screen |
| tabbypurr@gmail.com: Dec 12 10:14AM -0800 On Wednesday, 11 December 2019 20:45:20 UTC, Ralph Mowery wrote: > Those were new ones in the 25 pack. > They were checked with a Fluke 87 that had been sent out about 6 months > before to a lab that verified it to the NIST to be in caliberation. Yes, comp are known for drifting & sometimes going noisy. The high R values are much worse for drifting upward, since the internal contact points between grains are both smaller & fewer. NT |
| whit3rd <whit3rd@gmail.com>: Dec 13 12:00AM -0800 On Wednesday, December 11, 2019 at 1:58:19 PM UTC-8, Trevor Wilson wrote: > > And some of us (7-10% male, <1% female) are red/green colour challenged, > **The very first test I had to pass, before entering the electronics > biz, was a colour blind test. There's hope for the ten percent, though: cellphones can scan the codes for ya. <https://play.google.com/store/search?q=resistor%20color%20code%20scanner&c=apps> |
| tabbypurr@gmail.com: Dec 13 03:55AM -0800 On Friday, 13 December 2019 08:00:57 UTC, whit3rd wrote: > > biz, was a colour blind test. > There's hope for the ten percent, though: cellphones can scan the codes for ya. > <https://play.google.com/store/search?q=resistor%20color%20code%20scanner&c=apps> ... at the price of malware. |
| etpm@whidbey.com: Dec 12 10:39AM -0800 I have read about noisy resistors but what makes then noisy and what exactly is the noise? Thanks, Eric |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Dec 12 11:00AM -0800 > exactly is the noise? > Thanks, > Eric http://www.resistorguide.com/resistor-noise/ Peter Wieck Melrose Park, PA |
| Mike Coon <gravity@mjcoon.plus.com>: Dec 12 08:05PM In article <63da826d-85c7-4b45-84c7-376d050ff3a7@googlegroups.com>, peterwieck33@gmail.com says... > http://www.resistorguide.com/resistor-noise/ > Peter Wieck > Melrose Park, PA The interesting discussion provides an equation for the noise level that has no term for a material characteristic. Then goes on to say that there are quiet and noisy constructions. This seems to me a contradiction which is not resolved! Mike. |
| John Robertson <spam@flippers.com>: Dec 12 01:42PM -0800 On 2019/12/12 12:05 p.m., Mike Coon wrote: > there are quiet and noisy constructions. This seems to me a > contradiction which is not resolved! > Mike. Also, some resistors are only noisy under power (load). The Heathkit Audio Signal Tracer had a NOISE function where it would put about 75 - 100VDC across a resistor using the audio probe and if the resistor was noisy you could hear it... Handy test on tube sets! John :-#)# -- (Please post followups or tech inquiries to the USENET newsgroup) John's Jukes Ltd. MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3 (604)872-5757 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out." |
| Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net>: Dec 12 05:35PM -0500 >> Thanks, >> Eric > http://www.resistorguide.com/resistor-noise/ That's a really bad article. All resistors have Johnson (thermal) noise, which is white (i.e. flat with frequency). Resistors of the same value all have the same Johnson noise, but they differ a lot in their low-frequency noise. Some types of resistor, e.g. thick film, cermet, and carbon film, exhibit large fluctuations in conductance. Those don't cause problems if there's no DC voltage applied, but if there is, the conductance fluctuations turn into noise currents with an approximate 1/f power spectrum. Because of that 1/f, these types of resistor are very noisy at low frequency when there's DC applied. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com |
| tabbypurr@gmail.com: Dec 12 06:28PM -0800 On Thursday, 12 December 2019 22:35:22 UTC, Phil Hobbs wrote: > frequency when there's DC applied. > Cheers > Phil Hobbs And a 'noisy resistor' is one that has become faulty in that it generates a lot of extra noise. Classic issue with carbon comps. NT |
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