Questions tagged [dummy-load]

A "dummy load" is a replacement element for an item that would normally function as an electrical load.

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94 views

Where did I miscalculate ohms law in my experiment?

I thought I finally had a grasp on how ohm's law works but when I set up an actual experiment, the numbers don't match up. To keep a long story short, I converted a computer power supply into a lab ...
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3answers
78 views

Electronic load, Problem turning MOSFET on

I am trying to make an adjustable dummy load to test a 12V supply, I’m having trouble with the op-amp feedback circuit. Attached is a simplified schematic. I have tried lots of things and stripped it ...
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44 views

Which wire should I use as dummy load for this specific PSU

I'd like to make lab power supply out of my old ATX Power supply. I am beginner in electrical engineering and this project seems pretty straightforward. I've checked many tutorials about it and ...
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74 views

Electronic load for negative voltage PSU

I am making a MOSFET based electronic load to test my PSU rails. Below is a simplified version of my circuit with V2 as the PSU that is being tested. I want to be able to test negative voltage rails ...
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35 views

reactive power for power meter test (load bank)

I want to test a power meter and I need to test both active and reactive power. I use a resistive load bank to test active power. Now I want to see power meter performance in reactive loads. For ...
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3answers
58 views

How do I determine the range of wire wound adjustable resistor?

I'm looking at buying a 300W tubular adjustable resistor. Like this: https://www.digikey.com/product-detail/en/vishay-dale/RBEA03001R000KFB00/541-10193-ND/9765057 Digikey has four part numbers in ...
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4answers
129 views

Stress testing a PCB’s current handling capability?

I’ve produced a simple unregulated power supply PCB, consisting of: AC input terminals Fuse 4 rectifier diodes Filter/smoothing capacitors DC output terminals Only when the PCBs arrived did I get ...
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2answers
216 views

Thermal Management for Arcol HS50/HS100 50/100W Wirewound resistors

I'm designing a 100W dummy load for a guitar amplifier using Arcol HS50 and HS100 resistors. Here's a link to the datasheet: http://www.arcolresistors.com/wp-content/uploads/2014/03/HS-Datasheet.pdf ...
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0answers
194 views

4-wire voltage sensing for DC load

I'm building an electronic DC load. I'd like to implement voltage sensing (4-wire sensing). I made this schematic: Input voltage can be up to 60V, this circuit basically divides it by 6, and output ...
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2answers
1k views

AC analysis of opamp loop in LTspice

I'm building an electronic DC dummy load and have a problem with stability/oscillations. This is my circuit: Vset - controls current, when set to 100mV it makes 500mA at the shunt Vout1 - Vshunt ...
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4answers
800 views

Problem with opamp stability in DC load

I'm trying to make DC load up to 20A with 1mA precision. Current sense resistor is 5mΩ, so the voltage on this current sense will be from 5μV to 100mV. I picked LTC2050HV (datasheet) which have very ...
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2answers
953 views

Can I use two 10 ohm 5 watt resistors instead of one 5 ohm 10 watt resistor?

I am working on converting an old ATX PSU to a lab bench power supply, and the guide I follow is putting a 5 ohm 10 watt dummy load resistor on the 5 V supply line. I don't have resistors of this ...
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1answer
909 views

Need help to find correct values for dummy load resistor

I am working on converting an old ATX PSU to a DIY lab bench power supply. Everything is going well, but I can't seem to find out the correct dummy resistor load values. The 3.3v rail has 22A and the ...
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4answers
436 views

Cheapest dummy load? 450w, 15V, 30A, only for a few seconds

What is the cheapest and simplest way to dummy load 450w, 15V, 30A, only for a few seconds? I would like to measure the max output capability of an MPPT charger controller, basically as a "all losses ...
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2answers
1k views

Using a DC Electronic Load vs power resistors (dummy load)

When setting up a test to evaluate a DC power supply, would using a power resistor suffice? I have a 5 V power supply hooked up directly to a 5Ω 20 W resistor to pull a constant current of 1 A. When ...
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1answer
173 views

What's the purpose of the resistor in a 3A load box

There is a resistor R5 in the 3A load box below. It seems it add some positive feedback to Q1, but I'm not sure. What's the exact reason to add it? The circuit comes from here.
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669 views

Constant Current Load ampere measurement

I have the following circuit that I am building, a constant current load): I am using a 9 volt battery and a 1.5 volt battery to power the circuit. My load under test is a AA battery. Based on this ...
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2answers
265 views

Can aluminum-housed resistors be used as dummy load for battery testing (etc.)?

I want to buy me one higher-quality resistor to have a durable and stable dummy load element suitable for use in battery testing and other purposes. I've come across a 100 ohms / 10 W one which is ...
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1answer
1k views

Solar charging using or not using a dummy (dump) load

I'm in the process of designing a small solar regulator / charger (no more than 5A) for sealed lead acid batteries. I have put a working prototype together and all seems to be working. However, ...
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1answer
223 views

Some problems with my dump load controller

The requirement is an automatic dump load controller; for balancing lead acid or lifo batteries. While the input voltage is above 1.75V the circuit should dump 10A into the load continuously. ...
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2answers
221 views

Adding voltage divider to output of power amp concerns

I have a load box I use to test and burn in analog audio power amplifiers. Each load box is tailored for a specific amplifier circuit and for one of the load boxes I would like to add an LED that ...
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4answers
15k views

Simple, Variable High Current Dummy Load

I'm working on a power supply build and need a dummy load. I've found many mentions here that are good for a few amps, but I need one that's good for 30A or more... at 5V. I thought about just using ...
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3answers
1k views

Input Protection for an Electronic Load

I'm currently working on a dummy load designed for testing small power supplies less than about 10V. I'd like to provide reverse input protection to prevent the op-amps from being damaged. Because the ...
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2answers
10k views

Creating a specific volt/current “test load”

Working on a complex power supply, but to test its limits I would like to create a set of test loads of specific voltage/current. There are several devices for creating a set load, but they seem to ...
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2answers
9k views

ATX PSU: Simple dummy load?

To use an ATX supply outside of a PC while preventing output voltage to run away at low/no load, can I just use a couple of diodes in series to provide some kind of voltage-dependent load? Like: ...
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3answers
320 views

Load generator for testing power supplies

I have some DC-DC power supplies that I would like to test. (about 10 or so). PSU specs: Input 6-30V DC Output 8V DC, 2.5 Amps max. As I don't have the budget for a DC Load generator, I'm looking ...
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9answers
578 views

How to dissipate a lot of current

Lets say I want to test out a sine wave 120V 15Amp inverter by drawing 15 amps of resistive load. How can I draw this without generating very much heat, and optimized for as small as possible.