Report to Moderators
I think this message isn't appropriate for our group. The Group moderators are responsible for maintaining their community and can address these issues.
Link to Xieyuan Electronic
Report to Groups.io SupportI think this violates the Terms of Service. This includes: harm to minors, violence or threats, harassment or privacy invasion, impersonation or misrepresentation, fraud or phishing.
If you want to learn more, please visit our website glass glaze resistor.
> But if board space is at a premium
Then your priorities are wrong.
"Sound" and "Maintainability" are more important than board space.
> they after blow up the resistor? or they buy a 7G resistor and paint the line.
Call your regular supplier of crates of resistors, ask them to build some customs that don't get any carbon/metal applied, just a ceramic body with two leads.
Then put a tiny bit of carbon on. Pencil, aquadag (carbon, alcohol, and a binder), or what we here used to call India Ink (plain drafts-man's or fountain-pen ink) which is mostly water and carbon, with a little ox-gall binder.
> how we can measure that resistance?
Not easily; but special tubes or ordinary FETs can read nanoAmps. 70V across 7Gig gives 10nA. Or another way: a 7Gig and a 7Meg makes a 11:1 divider, put 100V across it and see if you get 9V out. With common bench VTVMs, you have to deduct the meter's 11Meg input resistance from the 7Meg reference, just math.
Or put it in the head-amp with a dummy capsule. If the cathode voltage is wrong, the resistor has too many Gigs; if the bass response slumps or the bass-noise is high, the resistor is too small. You don't need to know the resistor's actual value, just that it gives your best compromise between draining grid leakage and injecting thermal noise into the system.
> How much current flows thru the 1 gig resistor in a typical mic circuit?
Grid leakage. Less than a nanoAmp.
> What would be the max voltage across that resistor?
Same as the basic body that you drew it on. 1/2W resistors are usually rated 250V or 400V. Some of that is the carbon, but go much over these numbers and the ceramic may break down. This is utterly unimportant in mike use, unless you are testing the resistor with brute force. (7,000V across 7Gig would give an easy to measure 1mA, but probably an arc.)
> Do you need current to make noise?
Atoms won't stop wigging, or not at any temperature you want to work in. So any resistance has a noise.
Contact us to discuss your requirements of all industial resistor manufacturer. Our experienced sales team can help you identify the options that best suit your needs.