The simplistic Salas low voltage shunt regulator - Page 154

quanghao · 21st November 2009, 12:49 AM

Quote:

Originally Posted by massimo

Quanghao, tell your friend to reduce the lentgh of the black cables connecting the shunt board to the Dac pcb to the bare minimum. Those cables must be very short if you want to get fully advantage of the very low output impedance of the power supply.

Ok! thank Massimo!

RCruz · 21st November 2009, 12:24 PM

Hi Salas

I bypassed the 10r R1 with a 47r and am now reading 250mA between the smoothing cap and the shunt... (I am testing the shunt without any load).

Is this the correct way to measure shunt´s working current ?

Regards
Ricardo

stormsonic · 01:11 PM

@RCruz
R1=10 Ohm, bypassed with 47 Ohm. Total resistance = 8.24 Ohm

Measure voltage drop across this paralleled resistor. Divide voltage with resistance to get current. For 250mA voltage drop should be approx. 2.06V

Parallel resistance Calculator

RCruz · 03:55 PM

My measurements are 8.39r on R1, 1.99Vdrop on R1 so I calculated 0.237A... but measuring the current flow in the shunt input I get 0.25A.....All this without loading.

How can I explain the current diferences ?

Ricardo

Salas · 21st November 2009, 04:18 PM

Dvm?

RCruz · 21st November 2009, 05:37 PM

Probably

I settled for 10r//27r
Vdrop R1 = 1.964v
Current should be 265mA.

These are the measurements on the 4wire shunt I am now going to try !

It gets hot.... 76ºC on the power mosfet but I have good sinks.

Ricardo

RCruz · 21st November 2009, 05:38 PM

My browser makes me repeat posts

Salas · 21st November 2009, 05:43 PM

RCruz · 21st November 2009, 06:55 PM

Looks like this

Salas · 21st November 2009, 06:58 PM

I always liked those green perfboards you use. I never seen them in stores here. You know, the sinks are rather small for the current. The IRFPs are dogs though.

21st November 2009, 01:10 PM	#1533
stormsonic diyAudio Member Join Date: Aug 2008	@RCruz R1=10 Ohm, bypassed with 47 Ohm. Total resistance = 8.24 Ohm Measure voltage drop across this paralleled resistor. Divide voltage with resistance to get current. For 250mA voltage drop should be approx. 2.06V Parallel resistance Calculator Last edited by stormsonic; 21st November 2009 at 01:11 PM. Reason: Link added

21st November 2009, 03:53 PM	#1534
RCruz diyAudio Member Join Date: Sep 2006 Location: Cascais Blog Entries: 1	My measurements are 8.39r on R1, 1.99Vdrop on R1 so I calculated 0.237A... but measuring the current flow in the shunt input I get 0.25A.....All this without loading. How can I explain the current diferences ? Ricardo Last edited by RCruz; 21st November 2009 at 03:55 PM.

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21st November 2009, 12:24 PM	#1532
RCruz diyAudio Member Join Date: Sep 2006 Location: Cascais Blog Entries: 1	Hi Salas I bypassed the 10r R1 with a 47r and am now reading 250mA between the smoothing cap and the shunt... (I am testing the shunt without any load). Is this the correct way to measure shunt´s working current ? Regards Ricardo

21st November 2009, 04:18 PM	#1535
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Dvm?

21st November 2009, 05:37 PM	#1536
RCruz diyAudio Member Join Date: Sep 2006 Location: Cascais Blog Entries: 1	Probably I settled for 10r//27r Vdrop R1 = 1.964v Current should be 265mA. These are the measurements on the 4wire shunt I am now going to try ! It gets hot.... 76ºC on the power mosfet but I have good sinks. Ricardo

21st November 2009, 05:38 PM	#1537
RCruz diyAudio Member Join Date: Sep 2006 Location: Cascais Blog Entries: 1	My browser makes me repeat posts

21st November 2009, 05:43 PM	#1538
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece

21st November 2009, 06:58 PM	#1540
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	I always liked those green perfboards you use. I never seen them in stores here. You know, the sinks are rather small for the current. The IRFPs are dogs though.

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