Need simple transformer - but nobody sells it? - Page 1
Forum section: electronics / beginners

author: FriedMule
author_rank: Frequent Contributor
timestamp: January 24, 2021, 01:07:32 am
content: Hi I have searched about every component shop I can remember but have not found what I need.240VAC to -8VDC — 0 — +8VDC min 3VA6 it can maybe be 9VDC, but it will only add to the heat and I hope to avoid heat if possible.How do I get such a transformer?

author: langwadt
author_rank: Super Contributor
timestamp: January 24, 2021, 01:18:29 am
content: Quote from: FriedMule on January 24, 2021, 01:07:32 ama transformer doesn't output DC, you need a powersupply

author: ledtester
author_rank: Super Contributor
timestamp: January 24, 2021, 02:30:55 am
content: Have a look at this page:https://www.hammfg.com/electronics/transformers/power/266Maybe a 266G14 will work for you if you use a low drop-out linear regulator.Or a 266G16.

author: FriedMule
author_rank: Frequent Contributor
timestamp: January 24, 2021, 02:45:56 am
content: Yes the VDC was a stupid mistake, I meant VAC. :-)Thanks for the link, are those of okay-ish quality, meaning above eBay? :-)

author: ledtester
author_rank: Super Contributor
timestamp: January 24, 2021, 02:52:30 am
content: Quote from: FriedMule on January 24, 2021, 02:45:56 amhttps://www.hammfg.com/about

author: FriedMule
author_rank: Frequent Contributor
timestamp: January 24, 2021, 02:58:59 am
content: Thanks for that link also, I am in no way surprised that they write highly about themselves, but is it true? :-)

author: dcarr
author_rank: Regular Contributor
timestamp: January 24, 2021, 03:09:34 am
content: Hammond is good.

author: james_s
author_rank: Super Contributor
timestamp: January 24, 2021, 04:12:19 am
content: Hammond is top notch stuff, at least it was. I've used their project boxes before and liked them.This should be very easy, there are lots of transformers in the right ballpark but maybe you could explain a bit more about your project? What is the ultimate voltage you wish to get out of it? Keep in mine the voltage out of the transformer is often considerably higher at light load than when fully loaded, and also when you rectify and filter AC the resulting DC voltage will be significantly higher than the AC out of the transformer.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 24, 2021, 04:33:49 am
content: Before the onset of SMPS transformers were much more widely available than they are now, but even then there were relatively limited numbers of standard parts. When you go to parts shops you are finding NOS of once standard transformers (120 or 240 V mains to either 6.3 V AC or 12 VAC for filament power in tubes, mains to 170-300 VAC for plate supplies, later came mains to mid range ac voltages for transistor based amplifiers and radios, along with a few impedance matching types 4, 8 or 16 ohm outputs) and surplus production of transformers that were custom ordered by builders of various things.When you want to specify input, output and capacity you are really narrowing the field. Your choices are to wind your own, order a custom job (very pricey) or make do with something you find. Or maybe get lucky.

author: james_s
author_rank: Super Contributor
timestamp: January 24, 2021, 04:41:10 am
content: Quote from: CatalinaWOW on January 24, 2021, 04:33:49 amI used an iron transformer in a product a few years ago, I selected a nice tidy potted toroidal part. They had them in a range of voltages, 6.3, 8V, 9V, something like that. Custom values available if you want a bunch of them but even in single quantities there was more than 6.3 and 12.6V, most center tapped.

author: WattsThat
author_rank: Frequent Contributor
timestamp: January 24, 2021, 04:44:04 am
content: Signal Split/Tran has that exact configuration for voltage but you’ll need to go with 6VA. $10.50 Qty 1 from DigiKey.https://www.digikey.com/en/products/detail/signal-transformer/DST-4-16/953071

author: WattsThat
author_rank: Frequent Contributor
timestamp: January 24, 2021, 04:54:48 am
content: Another one with chassis mount and flying leads, 5VA.https://www.digikey.com/en/products/detail/triad-magnetics/VPL16-300/4835125

author: Jwillis
author_rank: Super Contributor
timestamp: January 24, 2021, 09:39:55 am
content: Here's another transformer manufacturerhttps://www.antekinc.com/transformers/

author: drussell
author_rank: Super Contributor
timestamp: January 24, 2021, 03:14:57 pm
content: Quote from: FriedMule on January 24, 2021, 01:07:32 amThat should be an easy requirement to fill, there are many choices readily available.I even happen to have a tube of Tamura 3FD-416Digikey lists at least 17 different models that are 8 or 9 volt dual secondaries, 230 volt capable primary in the 3.2-6 VA range, and that's just a quick search in the standard through-hole PCB mount, mostly laminated style parts. There will also be flying-lead torroids and "chassis-mount" parts that meet your required specifications.examples here:Digikey - Power Transformers - Filtered