LM7812 regulator as shown on the D schematics will be fine. Looking at your FET relay connections, I see you are leaving the FET input and output floating. Better to ground the input in normal mode as shown in the eyelet board .pdf.
ODS 102 with 2x KT88s and built-in Dumbleator
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- martin manning
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Re: ODS 102 with 2x KT88s and built-in Dumbleator
Re: ODS 102 with 2x KT88s and built-in Dumbleator
OK, thanks Martin. I think that was a combination of a late night and a lot of copy/pasting.martin manning wrote: ↑Tue May 14, 2024 11:13 am LM7812 regulator as shown on the D schematics will be fine. Looking at your FET relay connections, I see you are leaving the FET input and output floating. Better to ground the input in normal mode as shown in the eyelet board .pdf.
Does this make more sense now?
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Last edited by bcmatt on Tue May 14, 2024 2:53 pm, edited 1 time in total.
- martin manning
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Re: ODS 102 with 2x KT88s and built-in Dumbleator
Looks good now.
Re: ODS 102 with 2x KT88s and built-in Dumbleator
Hello Matt --
There is no need to provide heatsink as even with higher input voltages are better than 90%. Concerns around SMPS noise are sensible to raise, however RECOM has broad experience supplying industrial and medical applications that have regulatory demands for clean operation and my experience to-date has been that they are quite quiet. I see other companies including TI also offering similar product but have no first-hand experience to share.
FWIW.
..
RECOM makes a series of LM78xx replacement devices using switch-mode DC-DC regulation that I have found worth the trouble. Here is a data sheet for 1A "TO220" devices: R-78C-1_0.
There is no need to provide heatsink as even with higher input voltages are better than 90%. Concerns around SMPS noise are sensible to raise, however RECOM has broad experience supplying industrial and medical applications that have regulatory demands for clean operation and my experience to-date has been that they are quite quiet. I see other companies including TI also offering similar product but have no first-hand experience to share.
FWIW.
..
Re: ODS 102 with 2x KT88s and built-in Dumbleator
Hi Didit,didit wrote: ↑Thu May 16, 2024 5:12 pm RECOM makes a series of LM78xx replacement devices using switch-mode DC-DC regulation that I have found worth the trouble. Here is a data sheet for 1A "TO220" devices: R-78C-1_0.
There is no need to provide heatsink as even with higher input voltages are better than 90%. Concerns around SMPS noise are sensible to raise, however RECOM has broad experience supplying industrial and medical applications that have regulatory demands for clean operation and my experience to-date has been that they are quite quiet. I see other companies including TI also offering similar product but have no first-hand experience to share.
Thanks for chiming in. Sorry for my ignorance, but I'm curious about the advantages it provides. Is it just the built-in heatsinking, or other things too? Is it a direct replacement in the schematic, or does it also remove some of the need for filtering?
As per your suggestion, I'm looking at this one for $15:
https://www.mouser.ca/ProductDetail/919-R-78C12-1.0
vs what I was going to get before for $2.50:
https://www.mouser.ca/ProductDetail/926-LM7812CT-NOPB
Re: ODS 102 with 2x KT88s and built-in Dumbleator
Hello Matt --
The RECOM design, while a "pin-out" functional replacement, is unique vs classic LM linear regulator designs. There is a tiny switch-mode DC-DC supply within, and it's therefore is quite efficient -- i.e., has minimal heat output regardless of input to output voltages ratio and load current. So no heat sink required regardless; whereas the original linear regulator design might well require sinking as in worst-case will dissipate more power as heat than it delivers through to the useful circuit.
Best .. Ian
Really have jumped in price since my last order some years back. I don't recall precisely, but roughly $6 each in quantity 10. At those "today" prices I'll reluctantly withdraw the suggestion.bcmatt wrote: ↑Mon Jun 03, 2024 5:27 pmHi Didit,didit wrote: ↑Thu May 16, 2024 5:12 pm RECOM makes a series of LM78xx replacement devices using switch-mode DC-DC regulation that I have found worth the trouble. Here is a data sheet for 1A "TO220" devices: R-78C-1_0.
There is no need to provide heatsink as even with higher input voltages are better than 90%. Concerns around SMPS noise are sensible to raise, however RECOM has broad experience supplying industrial and medical applications that have regulatory demands for clean operation and my experience to-date has been that they are quite quiet. I see other companies including TI also offering similar product but have no first-hand experience to share.
Thanks for chiming in. Sorry for my ignorance, but I'm curious about the advantages it provides. Is it just the built-in heatsinking, or other things too? Is it a direct replacement in the schematic, or does it also remove some of the need for filtering?
As per your suggestion, I'm looking at this one for $15:
https://www.mouser.ca/ProductDetail/919-R-78C12-1.0
vs what I was going to get before for $2.50:
https://www.mouser.ca/ProductDetail/926-LM7812CT-NOPB
The RECOM design, while a "pin-out" functional replacement, is unique vs classic LM linear regulator designs. There is a tiny switch-mode DC-DC supply within, and it's therefore is quite efficient -- i.e., has minimal heat output regardless of input to output voltages ratio and load current. So no heat sink required regardless; whereas the original linear regulator design might well require sinking as in worst-case will dissipate more power as heat than it delivers through to the useful circuit.
Best .. Ian