Powerboard question

[Oddvar R]

That looks interesting, but I don't get where the legs are going?

[pompeiisneaks]

That's what I was mentioning as well, are you not using one? I've not pored over all dumbles, but the schematics I've seen and build used a lm7812 to ensure consistent 12V to the relays.

Does yours have one already? 8.6V doubled should be 17VDC then into the 12V regulator should handle it. The max input VDC i see on at least the datasheet I'm looking at is 35VDC and with it screwed to the chassis you've got a huge heatsink

~Phil

[Oddvar R]

[quote=pompeiisneaks post_id=409380 time=1583944163 user_id=16952]
That's what I was mentioning as well, are you not using one? I've not pored over all dumbles, but the schematics I've seen and build used a lm7812 to ensure consistent 12V to the relays.
[/quote

I am using this layout?

[Oddvar R]

So I could/should use this?:

[pompeiisneaks]

Oh ok, so that one, for some reason, doesn't use one? Weird. I'd guess that you'd want to ensure that the higher VDC isn't going to hurt a 12V Relay, or as noted by martin, add in an LM7812 like the other dumbles say #124 for reference.

I'd just make sure to use a small terminal strip like they do so you can bolt the LM7812 to the chassis to give it more heatsinking since you'll be pushing a bit higher voltage into it. Then you'll get a solid 12VDC out of it.

Edit: yes you posted before I could finish the above, that'e exactly right. Just the new component, the other parts are likely almost identical to get the voltage enough for your use. Then the regulator will drop the voltage to 12VDC out.

~Phil

[martin manning]

That looks interesting, but I don't get where the legs are going?

You need to add one turret or eyelet between the two where the 56ohm resistor is connected now. Pins 1, 2, and 3 are lower-right to upper-left in the layout I posted. The regulator is not dissipating much power, so a small bolt-on heat sink is all that’s needed. Easy.

[pompeiisneaks]

That looks interesting, but I don't get where the legs are going?

You need to add one turret or eyelet between the two where the 56ohm resistor is connected now. Pins 1, 2, and 3 are right to left in the layout I posted. The regulator is not dissipating much power, so a small bolt-on heat sink is all that’s needed. Easy.

Good to know, I definitely don't know enough about heatsinking to understand how you'd calculate it. Any tips on a good method to understanding that?

~Phil

[Oddvar R]

Luckily I had a regulator, I am just wonder where I should wire the input and outputs to it from?

[pompeiisneaks]

Looking at a datasheet should help.

here's one for a TI version.

Pin 1 is the 'input' or your rectified 18ish volts from the voltage double
Pin 2 is the ground, connect that to your ground of the doubler circuit
Pin 3 is the output, which sends the 12VDC to your relay.

7812.png

~Phil

[martin manning]

I drew the TO-220 style as viewed from the mounting tab end.

[Oddvar R]

I put in the regulator like this, will that be ok, and how should the cabling be from the board??

[Oddvar R]

I bought a bolt on sink from UK, takes awhile to get here. But I will try that solution. As soon as I understand it.

[martin manning]

Well, now that you have added the regulator to the chassis you don't need to use my plan to put it on the board. Connections are as shown below. Delete the 56 ohm and relocate the 1k.

[Oddvar R]

I am impressed, very nice of you to take your time to draw this. Thank you.

I now how 11.99 dc between ground and output on the regulator?
Is that how it should be?

[pompeiisneaks]

Exactly.

You should now also be able to trigger the relays w/o any issues so long as you get 12VDC relays.

~Phil