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  • Author Author: Robert Peter Oakes
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The Modular Bench Power Supply ++ - Simple Display Setup

Robert Peter Oakes

This is the start of the next blog in my series for the LAB bench power supply, in this video I will explore an option of using dedicated Digital displays to show the current and Voltage and how having a display with differential inputs can help eliminate errors

 

Back to main PSU blog http://www.element14.com/community/groups/test-and-measurement/blog/2014/09/15/the-modular-bench-power-system-the-essential-diy-build-for-every-ee-student-and-old-timer-alike

 

 

I will be adding the schematics by the weekend, in the meantime, enjoy the video

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  • Great video Peter,

     

    I was not aware that those little power meters were available.

     

    I will have to pick some of them up.

     

    DAB

  • in reply to DAB

    there not actually power meters, the ones I got from Newark/Farnell are simply 5V powered, 3.5 digit, +-200mV FSD. (I know an analogue term)

     

    but I used a select low value resistor to convert the current into a 0-200mV range representing 0-2A, the one used for voltage is simply connected to the low side of a 100:1 resistor network divider, simple as that.

     

    I will provide schematics for it.

     

    Also as a Heads up. Vishay Precision Group (VPG) , remember the webinar that recently showed from Powertron, well this is them, they have sent me a selection of sample 4 terminal (Kelvin connection ) resistors of low values (1ohm down to 0.01Ohm) and heavy power versions too, with something like 2ppm temp co-efficient which is awesome and a couple even 0.1% tolerance too.

     

    There also sending me some HIGH precision resistor divider network devices in something like a TO92  and TO220 packages, the divider networks are something like 0.01% accurate and perfect for instrumentation OPAMP feedback loops or for scaling to a display input, perfect for instrumentation

     

    I will be dedicating a whole episode on them, well the principle of kelvin connections,purpose built power sense resistors, the choice of cabling in a build and the benefits of precision components

Comment
  • in reply to DAB

    there not actually power meters, the ones I got from Newark/Farnell are simply 5V powered, 3.5 digit, +-200mV FSD. (I know an analogue term)

     

    but I used a select low value resistor to convert the current into a 0-200mV range representing 0-2A, the one used for voltage is simply connected to the low side of a 100:1 resistor network divider, simple as that.

     

    I will provide schematics for it.

     

    Also as a Heads up. Vishay Precision Group (VPG) , remember the webinar that recently showed from Powertron, well this is them, they have sent me a selection of sample 4 terminal (Kelvin connection ) resistors of low values (1ohm down to 0.01Ohm) and heavy power versions too, with something like 2ppm temp co-efficient which is awesome and a couple even 0.1% tolerance too.

     

    There also sending me some HIGH precision resistor divider network devices in something like a TO92  and TO220 packages, the divider networks are something like 0.01% accurate and perfect for instrumentation OPAMP feedback loops or for scaling to a display input, perfect for instrumentation

     

    I will be dedicating a whole episode on them, well the principle of kelvin connections,purpose built power sense resistors, the choice of cabling in a build and the benefits of precision components

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