The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB

[nautibuoy]

Thanks Gary

 

[xrk971]

The SLB verification build PCBs just arrived. I will try to build it up this weekend. Board looks great - Thank you to jhofland for the beautiful layout!

 

[gary s]

The boards do look good, hopefully your build will find no problems. I have all the parts together ready to build (apart from any late changes you might suggest after building and testing) as soon as I get my boards, thanks again X.

 

[Vunce]

The SLB’s look sweet X!
Very nice layout jhofland, the edge mounted CRC resistors will love their open space

 

[xrk971]

I think I am ready to start sending invoices out for the SLB. Pricing will be $20 ea. They will be 2mm thick, 2oz copper and ENIG. Shipping will be $5 in USA, $10 to CAN, and $15 to everywhere else.

Please send me your PayPal info, along with country and number of boards to order.

 

[gary s]

Thanks X, pm sent.

 

[xrk971]

GB status update:

baswamin - 2 boards - invoice sent
meanie - 2 boards
jwjarch - 2 boards
gary s - 2 boards - invoice sent
nautibuoy - 2 boards
antoniopf1972 - 2 boards

 

[ravid]

2 boards please if I'm not too late.

 

[xrk971]

GB Update:

baswamin - 2 boards - invoice sent
meanie - 2 boards
jwjarch - 2 boards
gary s - 2 boards - invoice sent
nautibuoy - 2 boards
antoniopf1972 - 2 boards
ravid - 2 boards

Ravid, and all, please PM me your PayPal info and I will send invoice.

 

[gary s]

Hi x, my Paypal payment was just sent back to you, thanks again.

 

[jwjarch]

PM sent, X! Thanks!

 

[xrk971]

GB status update

baswamin - 2 boards - invoice sent
meanie - 2 boards
jwjarch - 2 boards - invoice sent
gary s - 2 boards - Paid
nautibuoy - 2 boards
antoniopf1972 - 2 boards - invoice sent
ravid - 2 boards - invoice sent

 

[antoniopf1972]

Payment sent. Thank you

 

[Gricko]

SLB

baswamin - 2 boards - invoice sent
meanie - 2 boards
jwjarch - 2 boards
gary s - 2 boards - invoice sent
nautibuoy - 2 boards
antoniopf1972 - 2 boards
ravid - 2 boards

Gricko - 2 boards​

 

[poseidonsvoice]

baswamin - 2 boards - invoice sent
meanie - 2 boards
jwjarch - 2 boards
gary s - 2 boards - invoice sent
nautibuoy - 2 boards
antoniopf1972 - 2 boards
ravid - 2 boards
Gricko - 2 boards
poseidonsvoice - 2 boards

 

[xrk971]

GB status update:

baswamin - 2 boards - Paid
meanie - 2 boards - need PayPal address
jwjarch - 2 boards - Invoice sent
gary s - 2 boards - Paid
nautibuoy - 2 boards - Need PayPal address
antoniopf1972 - 2 boards - Paid
ravid - 2 boards - Paid
Gricko - 2 boards - Invoice sent
poseidonsvoice - 2 boards - Invoice sent

 

[xrk971]

GB status update

baswamin - 2 boards - Paid
meanie - 2 boards - Invoice sent
jwjarch - 2 boards - Paid
gary s - 2 boards - Paid
nautibuoy - 2 boards - Need PayPal address
antoniopf1972 - 2 boards - Paid
ravid - 2 boards - Paid, Invoice sent for Simple PSU ship same time
Gricko - 2 boards - Invoice sent
poseidonsvoice - 2 boards - Paid
Bkdog - 2 boards - Invoice sent

 

[yoaudio]

baswamin - 2 boards - Paid
meanie - 2 boards - Invoice sent
jwjarch - 2 boards - Paid
gary s - 2 boards - Paid
nautibuoy - 2 boards - Need PayPal address
antoniopf1972 - 2 boards - Paid
ravid - 2 boards - Paid, Invoice sent for Simple PSU ship same time
Gricko - 2 boards - Invoice sent
poseidonsvoice - 2 boards - Paid
Bkdog - 2 boards - Invoice sent
yoaudio - 2 boards

 

[Mark Johnson]

We are using KOA Speer non inductive cement filled rectangular metal plate 5W resistors. A pair of 0.1ohm in series passing 5A is dissipating 2.5W ea - well under rating.

Data sheet is page 211:
http://koaspeer.com/pdfs/brochures/KOA_Catalog_2017.pdf

It's definitely not something you want to grab with your fingers when it is running, but doesn't melt its own solder at least and we are giving it room for air flow. If folks are concerned about keeping temps low, use four 0.22R in series parallel and dissipation will be about 1.25W each for maybe 65C temps.

I added a few of those KOA Speer rectangular metal plate resistors, part type "BPR", to a recent Mouser order. They were less than a dollar, it's a very low cost to perform some fun experiments.

I bought the 1.0 ohm resistor from Mouser, and attached it to my lab equipment using a "4 point Kelvin connection". Current is forced from the red clip to the black clip. Voltage is sensed from the yellow clip to the white clip. Notice that the yellow and white clips are attached in places where the high current is NOT flowing. There is no IR drop to pollute the voltage measurement.

I carefully adjusted the power supply output voltage until 1.5862 volts appeared across the 1 ohm resistor, measured at the yellow clip and the white clip. Thus the power dissipated in the resistor was (1.5862 * 1.5862 / 1.00) = 2.516 watts. That's my best attempt to match the 2.5 watts of dissipation, mentioned in the very first quote above.

I used a Type-K thermocouple to measure the temperature of the BPR resistor body. The thermocouple bulb was pressed onto the resistor body right where the OMEGA symbol is printed, between the 1 and the J. Thermocouple temperature in this position was 95.6 degrees Celsius. Almost hot enough to boil water. Definitely hot enough to burn a hobbyist's fingers.

_

 

[xrk971]

96C sounds rigjt - no argument there. I did say you don’t want to grab it with your fingers when it’s running. 96C temp doesn’t bother the part though one bit.