Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [dummy-load]

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

A typical household example for a dummy load requirement would be the checking of used batteries for their remaining power. Due to their physical characteristics, simply holding the cables of a multimeter against the (+) and (-) side of a battery is never going to output the actual remaining voltage, because the load is missing (with a flashlight, the "load" would be the bulb, for instance). A dummy load (mostly a resistor) will then take the place of the load normally expected to be there (e. g. the bulb).

42 questions
11
votes
4 answers

Is there anything particularly special about a "short" and an "open" in a VNA calibration kit?

I would like to calibrate a VNA with the reference plane at the end of a male BNC feedline. Surprisingly, female SOL kits are hard to find. There are many BNC 50-ohm loads available but I'm having trouble finding a BNC open and a BNC…
KJ7LNW
  • 1,350
  • 6
  • 16
5
votes
2 answers

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 start in the $300+ level. I've found a circuit for…
ZacWolf
  • 171
  • 1
  • 1
  • 9
5
votes
3 answers

Is this avalanche rugged MOSFET suitable for linear operation?

I would like to create an active load which draws current(4 to 6A) from a 12V battery. Unfortunately, the shipping costs and delivery times have prevented me from buying Linear FETs directly from well known manufacturers. Instead, I have found this…
A.H.Z
  • 633
  • 2
  • 10
3
votes
4 answers

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: simulate this circuit – Schematic created using…
JimmyB
  • 3,823
  • 2
  • 18
  • 21
3
votes
3 answers

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 for a cost effective alternative to test with. I…
dip2013
  • 33
  • 2
3
votes
1 answer

Will a 10 Ω resistor create 2.5 W of dummy load on 5 V line (using an old ATX PSU)?

I am trying to understand something about dummy load resistors. I have an old ATX PSU. It has a 5 V line; maximum is 34 A, but it says it needs a minimum of 0.5 A. That means it needs a minimum load of 0.5 A to function properly, since its an ATX…
komrad2236
  • 399
  • 6
3
votes
3 answers

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 down to this. Basically when +In of the op-amp…
Benjamin
  • 135
  • 1
  • 7
3
votes
4 answers

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 included" way of measuring actual solar panel…
user95482301
  • 1,120
  • 3
  • 14
  • 37
3
votes
1 answer

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.
diverger
  • 5,828
  • 5
  • 43
  • 79
3
votes
4 answers

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 some high wattage LEDs or something but they all…
Adam Haile
  • 1,603
  • 5
  • 31
  • 50
2
votes
3 answers

Is there such thing as a load generator for testing a modular power supply unit?

I have built a modular power supply - and I was wondering if such thing exists to generate a mock load. I have two supply blocks and I need to make sure they are supplying adequate current. I can hook up a multimeter to check current fine but that…
Barry Chapman
  • 133
  • 5
2
votes
1 answer

50 ohm Dummy Load With 50dB Attenuator

I am designing a 50 ohm 10 watts dummy load for 100-1000MHz frequency range. The signal strength should not exceed -10dBm. The load must be able to dissipate 5 watts minimum, that is +37dBm. The output to the test equipment must be no more than…
Onur Can Saglam
  • 33
  • 4
2
votes
1 answer

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 creators of these instructed, that there should be…
sohacz
  • 21
  • 1
2
votes
2 answers

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 This is my 16 ohm dummy load. Worst case it will…
Avid Pro Tool
  • 501
  • 3
  • 14
2
votes
2 answers

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 value right now, can I instead put two 10 ohm 5 watt…
rebellion
  • 121
  • 1
  • 7
1
2 3