DHT Heater using VCCS - PCB or Kit (Possible Group buy)

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RhythMick
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#946 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by RhythMick »

andrew Ivimey wrote: Thu Apr 05, 2018 11:44 am I've done this tho not with Andrew's. The modules were variable and I was using 7.5 volts at an amp. The transistors / i.c.s were about six inches away from the modules. No probs.
Thanks. So unless Andrew advises otherwise I'll consider this an option.
Andrew
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#947 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Andrew »


So, is it OK to mount the transistors on heatsinks remotely and run wires to the boards?
Not sure it would be my first choice; it will certainly increase strays/parasitics and there was a lot of work in the layout of the PCB to keep noise to a minimum.

And, don' forget both transistors are carrying the full current, so reasonably sized wires would be required. As I said, they work better very close to the DHT and using as short a wires as practical.

Having said that, you can do what you want with them, but to be fair to everyone involved, they become your problem if they don't work.
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RhythMick
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#948 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by RhythMick »

Thanks Andrew.

One more question please. Are the heatsinks at ground potential or are they live?

Badly phrased. I mean are the backs of the transistors live, needing mica spacers?
Andrew
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#949 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Andrew »

I mean are the backs of the transistors live, needing mica spacers?
A isolating spacer is needed unless you replace the D44H11, providing you don't need to be in the upper end of the current specs, the regulator is an all plastic part.

Andrew
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#950 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Andrew »

OK, now that Easter is behind us I am in a position to start building up the group buy and, all being well, parts availability not withstanding, ship in a week or two.

There has been a few changes to the orders and so I have lost track of where we were. For the sake of clarity and to avoid disappointment, could everyone add the their order to this thread so that we build up a list of who want's what.

What I am after is you copy the previous post that includes the order list as it stands and add in what you need at the end.

This is self editing and avoids me making a mistake.

So person #1 adds their order.

Person #2 copies person #1's text and posts a new reply appending their order to the end preserving #1's text.

Person #3 copies person #1's and #2's text and posts a new reply appending their order to the end...

and so on.

thanks,

Andrew
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RhythMick
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#951 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by RhythMick »

Mick : 12 x large
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thomas
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#952 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by thomas »

RhythMick wrote: Sun Apr 15, 2018 8:42 pm Mick : 12 x large
4 x large ones please for me Thomas
davebms
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#953 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by davebms »

thomas wrote: Sun Apr 15, 2018 11:12 pm
RhythMick wrote: Sun Apr 15, 2018 8:42 pm Mick : 12 x large
4 x large ones please for me Thomas
2 large davedms
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Nick
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#954 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Nick »

I think he wants each reply to add to a list he can read, so

Mick : 12 x large
Thomas: 4 x large
davedms: 2 x large
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#955 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Michael L »

Mick : 12 x large
Thomas: 4 x large
davedms: 2 x large
Michael L 2 x small
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#956 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Andrew »

Yes please, thanks for clarifying that, Nick.

Andrew
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#957 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Michael L »

Mick : 12 x large
Thomas: 4 x large
davedms: 2 x large
Michael L 2 x large
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#958 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Andrew »

Neal, did you still want some?

thanks,

Andrew
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#959 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by Neal »

4 large please
Only the Sith deal in absolutes.
RhythMick
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#960 Re: DHT Heater using VCCS - PCB or Kit (Possible Group buy)

Post by RhythMick »

As per pm, amending mine (and adding Neal)

Mick : 16 x large
Thomas: 4 x large
davedms: 2 x large
Michael L 2 x large
Neal : 4 x large
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