470pF non polarized, non ceramic  - Page 1
Forum section: electronics / beginners

author: r00n
author_rank: Contributor
timestamp: December 04, 2023, 08:36:05 pm
content: I am makinghttps://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjY7K-y7_aCAxXQyDgGHegNCAEQFnoECBUQAQ&url=https%3A%2F%2Fwww.instructables.com%2F3340-Voltage-Controlled-Oscillator-Module-for-Modu%2F&usg=AOvVaw1fzwP18kthiOJkNYixX6-V&opi=89978449The BOM refers to "1x 470pF non polarized, non ceramic (you need something stable with temperature)". I only know the non polar ceramic caps and the polar canister caps and have no knowledge of other types.Could you please assist me if you have a moment? Thanks for your help.*fixed link

author: Slh
author_rank: Regular Contributor
timestamp: December 04, 2023, 08:44:10 pm
content: The link isn't working but from the description I don't know why an NP0/c0g ceramic cap wouldn't work. Alternatively, you want to look at silver mica or film caps. I can't remember what the best film material is for temperature stability but elsewhere on the internet will help.

author: bdunham7
author_rank: Super Contributor
timestamp: December 04, 2023, 08:46:20 pm
content: It sounds like they mean a film or metallized film capacitor, typically mylar, polypropylene or similar polymer films.https://www.digikey.com/en/products/detail/wima/FKP0C004700B00KSSD/9370033

author: Coordonnée_chromatique
author_rank: Frequent Contributor
timestamp: December 04, 2023, 08:47:31 pm
content: https://www.eddybergman.com/2020/01/synthesizer-build-part-18-really-good.html

author: wraper
author_rank: Unknown
timestamp: December 04, 2023, 08:49:28 pm
content: Actually the requirement is nonsensical. COG or NP0 ceramic capacitor like thishttps://eu.mouser.com/ProductDetail/TDK/FG28C0G1H471JNT06?qs=qf2ddTMq67XgQnSCHEHPgQ%3D%3Dis more stable than film (that was most likely meant) and will work just fine. Why in hell write what it shouldn't be instead of writing what it should be. Also I suspect that for some other capacitors "non polarized" requirement by itself is not adequate and you need something more stable than Y5V ceramic capacitor. Post the circuit here, not going to register just to see it.

author: floobydust
author_rank: Super Contributor
timestamp: December 04, 2023, 09:12:08 pm
content: TheCurtisIC CEM3340 VCO goes back to the 1980's, an era full of drifty ceramics.Today you would use a C0G or NPO. Mica costs a small fortune, $4-8ea. CD15FD471JO3.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 04, 2023, 10:11:06 pm
content: Ceramic capacitors come in different version. C0G version are actually quite good (better than most film types) when it comes to stability and they are perfectly available as 470 pF.Even in the 1980s they should have had C0G - maybe called by a different name. If needed there are also capacitors with defined positive and negative TC to compensate for other parts drifting.In the early days 470 pF may have been relatively large for a C0G cap, but todays it is absolutely no problem.There are more tricky ceramic type like X7R and X5R, but these are usually used only for higher capacitance, mainly for decoupling and similar tasks where the exact capacitance does not matter.With 470 pF a electrolytic version makes not sense - these are usually 0.5 µF and up, so at least 1000 x larger.

author: DavidAlfa
author_rank: Super Contributor
timestamp: December 04, 2023, 10:30:35 pm
content: Probably because the inmense majority of ceramic caps are x5r/x7r, not c0g, so they simply state to not use them to avoid issues.PP/MKT capacitors will do great.

author: TimFox
author_rank: Super Contributor
timestamp: December 04, 2023, 11:26:15 pm
content: Before MLCC ceramic construction was available, "disc ceramic" (one dielectric layer with two electrodes) capacitors were made for relatively high voltage, but low capacitance in NP0 (good) dielectric.For example, the Ceramite (originally Sprague) NP0 discs rated at 1 kV are still available up to 270 pF (0.89 inch diameter), but in N750 ceramic they are available up to 1000 pF (large negative tempco but good loss).So, when that design was made a stable disc ceramic capacitor was iffy at 470 pF, but mica capacitors were not yet overpriced.

author: Dan123456
author_rank: Regular Contributor
timestamp: December 05, 2023, 05:58:53 am
content: If it is the blue one on the top right of the red board (near the trim pots), that looks like a MKTFrom the picture though, it seems to say “1N” on the board but maybe there is just a 1N ceramic hidden behind it

author: r00n
author_rank: Contributor
timestamp: December 05, 2023, 07:52:44 pm
content: thanks, sorted.