Thanks for that, @Mooly - I got a bit confused by the BOM, as it says "for 12VAC supply" under notes near the 5V relay option. I did think it was off as it would be well over 10VDC rectified, but assumed there was something at play beyond my understanding. Turns out this is a rare instance of me actually being on the right track. So, thanks again for the clarification.
I don't actually have a transformer as yet (or even the board), as I'm in the preliminary 'can I get the parts and understand this' stage. Ideally I'd like to build a HoneyBadger, but I have a lot of reading and researching yet to get to that point! I'll look for a 9VAC toroid. Did you have a recommendation on VA for the transformer? Looks like almost anything would do?
I don't actually have a transformer as yet (or even the board), as I'm in the preliminary 'can I get the parts and understand this' stage. Ideally I'd like to build a HoneyBadger, but I have a lot of reading and researching yet to get to that point! I'll look for a 9VAC toroid. Did you have a recommendation on VA for the transformer? Looks like almost anything would do?
Thanks again. I'm a dingus - I was thinking about the primaries being in series (for 230VAC mains) and somehow thought that had anything to do with current on the secondaries.
I will take a look at el core and other transformers, too. I know people tend to prefer toroids for big transformers, wasn't sure if the same justifications applied for small ones.
I will take a look at el core and other transformers, too. I know people tend to prefer toroids for big transformers, wasn't sure if the same justifications applied for small ones.
Assuming two 115V AC primaries would be connected in series for 230 volt mains. The secondaries you can do as you wish, in parallel for double current or in series to double the voltage (current stays the same as each single winding). The phasing of the windings has to be correct in all cases.
Noted, thank you. That was makes sense (with my morning coffee).
Seems like most of the transformers I can access in the appropriate voltage and VA are PCB mount.
For example, this would do nicely:
https://www.altronics.com.au/p/m4318-powertran-9-9v-pcb-10va-toroidal-transformer/
I know I can get the little breakout PCBs for these from the usual iffy websites, but if anyone knows where I can get the nicer, fused kind (PCB or Gerber), I'd be most appreciative. Kind of like this kit, but scaled down for the 10VA dimensions:
https://www.jlmaudio.com/shop/world-transformer-kit.html?display_tax_prices=1
Seems like most of the transformers I can access in the appropriate voltage and VA are PCB mount.
For example, this would do nicely:
https://www.altronics.com.au/p/m4318-powertran-9-9v-pcb-10va-toroidal-transformer/
I know I can get the little breakout PCBs for these from the usual iffy websites, but if anyone knows where I can get the nicer, fused kind (PCB or Gerber), I'd be most appreciative. Kind of like this kit, but scaled down for the 10VA dimensions:
https://www.jlmaudio.com/shop/world-transformer-kit.html?display_tax_prices=1
I hear you. Honestly I'd be happy with that solution, too. That would probably rule out the HoneyBadger without a bit of rejigging then, as that seems to want something north of 40V for the supply. The reconfiguration you mention is a bit outside of my skillset right now. Might work with the new F5M with an 18v supply if I find suitable 12V relays.
I was reading up on relay substitution and found this article:
https://techcircuit.org/relay-substitution-and-coil-resistance/
Which has been helpful. Seems like there's a few equivalent options, however all the Omrons are now 360ohm coil resistance. That's just within the 10% the above article quotes, but I dunno whether it's better to go with the more exact (if less well-known brand) relays that are 400ohm.
eg. https://au.mouser.com/ProductDetail/Song-Chuan/833H-1C-S-12VDC?qs=Me3ZrpFQdnzTJnNcagt%2BNw==
I was reading up on relay substitution and found this article:
https://techcircuit.org/relay-substitution-and-coil-resistance/
Which has been helpful. Seems like there's a few equivalent options, however all the Omrons are now 360ohm coil resistance. That's just within the 10% the above article quotes, but I dunno whether it's better to go with the more exact (if less well-known brand) relays that are 400ohm.
eg. https://au.mouser.com/ProductDetail/Song-Chuan/833H-1C-S-12VDC?qs=Me3ZrpFQdnzTJnNcagt%2BNw==