Just make sure to stay within the safe operation area. banana connections. This This project is based on the common LM317T regulator, used as a current regulator. An adjustable current source would be more appropriate here, but I don’t have one, and this little unit is more versatile and cheaper to make. The circuit is a classic. Arduino DIY: constant current electronic dummy load. Range in this circuit depends on the sense resistor. cant you use a transistor for the same thing? The 1 Ohm power resistor helps share the power with the The CC and CR mode load simulations are useful for testing whether the output voltage of the UUT remains stable or regulated under different load conditions. 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Dave grabs a few junkbox parts and builds a useful constant current load for switch mode power supply, battery testing, and other applications. This is a constant current dummy load. I built the circuit up on some strip board and added some wires as there is no room on the breadboard for the heatsink. By using our website and services, you expressly agree to the placement of our performance, functionality and advertising cookies. Inspired by a design he saw on the EEVblog, [George Graves] put together this constant current dummy load. appropriate voltage/current rating should do, but I used an This is exactly what I want. The only consideration for the OpAmp supply is that it’s high enough so the OpAmp can bias the gate of the mosfet up to its saturation voltage. Here is the small list of parts that you will need (affiliate links): Ebay: Aliexpress: … A good opamp like lm324 can go from 0 to Vsupply – 1.5 volts, so you want your supply to be at least 1.5v more than the saturation voltage of the mosfet you’re using. adjusted :). After seeing the same Vblog i wanted to make this unit as well. It is quite easy to get this circuit to oscillate. Introduction: Arduino Programmable Constant Current Power Resistance Dummy Load. Yes, Please, 120 Node Rasperry Pi Cluster For Website Testing. I built this to help control current in an aluminum anodizing setup, so I hope to match the voltage close to what’s needed for my load, then put this inline to drop the excess voltage to keep the current where I want it. An electronic load, also known as a constant current dummy load, is a device design so a power supply can draw a certain amount of current without dissipating too much of heat. Load Current error – Up to Approximately 3mA. At 1 Volt 1 Amp produces 1 W. But if he sinks 10 V at one amp, it becomes 10 Watt. Basically, you dial in a current level, and it Here is the EEVblog #102 - DIY Constant Current Dummy Load for Power Supply and Battery Testing. The die-cast aluminum case is relatively thick, making it an excellent heat sink. An LM324 op-amp was used here. F12N10L, which is available from Farnell. Maximum Input Load Voltage - 32V; Maximum Input Load Current - 16A; Maximum Input Power Dissapation - 120W The current that a dummy load can handle is less of an issue in terms of heat as the power it can take up. Virtually indestructable. currently i'm using heater to replace power resistor but the current always drop when the heater generate heat. Our constant current load design is an iteration of a very popular design that you can find all over the internet, possibly either designed or made popular by Dave Jones from the EEVblog. The first link (for the EEVblog) is wrong. testing, this can get very hot, and I did in fact kill one transistor when using a heatsink which was too small, so I Problems, Martin As you can see, it’s equipped with a 4×16 character LCD display and, less obvious, a rotary encoder with push button. Constant power mode is achieved by calculating the desired set current via the measured load voltage. If the capacitor in the above circuit diagram is removed, the circuit will oscillate. Dummy-Load. It is a 5 Watt, .1 Ohm resistor. £4. Might be enough for simple cases. Samantha has added a new project titled implantable sbc. yikes. I got some fun looking Lorton's sites, I decided I will build a constant current dummy (Comment Policy). Please be kind and respectful to help make the comments section excellent. to a heatsink, especially if you use a smaller one. F12N10L, and swap the 24V supply for a 9V supply, and it should Operates over 3.3 to 40V, and at 0-3A. What we really like though, is he took fantastic pictures. is available from Farnell as product code 171-0614 for about It accurately sets the desired current via a 16bit DAC and reads both current and input voltage with a single-channel 16bit ADC each. will draw that amount of current, regardless of the voltage. It’s not meant to continuously sink current. So to make a device that provides a constant current no matter the load, we have to use negative feedback and convert the current flowing through our load into a voltage. accurately. As you can see, it’s equipped with a 4×16 character LCD display and, less obvious, a rotary encoder with push button. Basically, you dial in a current level, and it will draw that amount of current, regardless of the voltage. Assembled Variable Dummy Load. For the sense resistor I used 40 half-watt 10 ohm resistors, with a toggle switch to bypass 30 of them. The voltage input in this circuit goes up to 24V. Introduction. I have used it other bog standard op-amp will also probably work provided you It accurately sets the desired current via a 16bit DAC and reads both current and input voltage with a single-channel 16bit ADC each. get the power supplies correct. This is a nice simple circuit, which is easy and cheap to build, and very useful, especially if you want to design power supply circuits. Would You Like Fries With Your Insect Burger, Ma’am? Learn how your comment data is processed. Another section of the amplifier is configured as a gain amplifier. The device is called Constant Current Dummy Load which has a fully analog design and no digital logic in it. I make a PCB, but it actually works OK. A 500 ohm trimpot (requires separate power) and BDW93C + BC639 in a Darlington configuration. To test real capacity of a power supply, we need a load with variable current consumption. This article was inspired by this Hack a Day post, which is about building a dummy load using a FET and op. simply a 9V PP3 battery. This was only intended to be temporary till Guido has added a new project titled 10 Components for a Minimal Battery Powered ESP32. Instead, I've decided to purpose build a constant current dummy load. They pull a constant current regardless of the voltage of the supply. If we have high power variable resistor such as tapped wire-wound resistor, we can directly connect this resistor and make some measurement. Basic constant current dummy load using an Op Amp and a by-passing MOSFET is very easy to build and had been made quite popular following Dave’s video on EEVBlog. Jones' Video. This site uses Akismet to reduce spam. should be used instead, as this will allow a much smaller This is a nice simple circuit, which is easy and cheap to Thus the circuit is powered by an external 12V supply. Following some inspiration from both Dave Jones' and Martin The 1R resistor must be able to dissipate quite a bit of power. Therefore, at present maximum 24V, 5A load can be set by this dummy load. Updated: 15th December 2013, Oscillation dummy load! Order Your Parts! A load which can handle 1 W would only allow for 100 mA of current at this voltage. 1.02A from a 5V power supply. work fine. The power dissipated by the resistor is then given by I^2. He says that everything runs fine at 1 amp. PARTS LIST. The IRF540 MOSFET was also attached to a heatsink. 6.5 volts across a 1 ohm sense resistor means 6.5 amps, which will mean your resistor is dissipating over 42 watts. Ideally, a logic level MOSFET problem. amp.No doubt, this build is good, but according to the schematic it turns out that it is a constant current load. I made exactly that thing once, to test limits of a recently built power supply (LM317-based). [George’s] version extends the range of the original a little bit by running the op-amp at 8 volts. Learn more, http://www.elektor.com/magazines/2012/may/lossless-load.2135766.lynkx, http://www.edn.com/article/518938-Power_resistor_varies_in_value.php. In some cases it can be useful, but one can also be in need of a constant resistance load. the MOSFET to allow some current through the drain to the The circuit is ideal for driving LED arrays, laser diodes or any other circuit requiring a constant current supply. but even the 50W resistor got hot, so you may want to attach it I built it on a breadboard. By default, the current can be adjusted at a resolution of approximately 1mA/step. A general purpose dummy load shouldn’t need external power, and Re:load doesn’t. The first OP-AMP (IC1A), is configured as a voltage follower. single turn pot will work if you prefer). Absolute Maximum Ratings. Following some inspiration from both Dave Jones' and Martin Lorton's sites, I decided I will build a constant current dummy load. And here is some info from that: The circuit uses two OP-AMPs to set the constant current. There is an inaccuracy in the article. The MOSFET I used can dissipate mucho watts, but I’m limited by my heatsink. My article was published here: http://www.edn.com/article/518938-Power_resistor_varies_in_value.php. By pressing the encoder button, this resolution can be changed to 10mA/step and 100mA/step respectively. The op-amp buffers This makes it easier to to coarse adjustments. Basically, a voltage is set by a multiturn potentiometer (a to the use of an IRF540 MOSFET. That’s not nearly the same thing as shown here. Guido has updated details to 10 Components for a Minimal Battery Powered ESP32. The current that a dummy load can handle is less of an issue in terms of heat as the power it can take up. Re:load 2 is an adjustable constant-current load with several key properties: Cheap - just $20! This causes swapped it for a bigger one. Yes! MOSFET and assists in providing feedback to the op-amp. Stephen Coates' Website - stevecoates.net, Created: 17th November 2012 This dummy load has the following specifications: Maximum Input Load Voltage – 24V; Maximum Input Load Current – 8A; Maximum Input Power Dissapation – 50W; Operating Voltage – 5V; Power Source – USB or External Power Pack (5V) Minimum load current draw – 15mA – Due to op-amp offset. up to about 3.4A. For those who don’t know, an electric load (or dummy load) is a device used to simulate a load on a system for testing purposes. I used a 2.7°C/Watt heatsink which So, inspired by V1.0 of my Electronic Dummy Load which has 2 amp maximum I thought I'd build a bigger unit capable of up to 10 amps @ 25vdc (250watts). 8.9A seems like a lot in this case, but if I can keep the voltage drop across the mosfet small it’s doable. As per the power-law, it will support maximum 7A (P = I 2 R), but for the safe side, it is wiser to limit the load current maximum of 5A. any one have any link to some sort of article that shows how to make one? This Unlike conventional resistive loads, the dummy load maintains a constant but adjustable load current for voltages in the range of 40 volts. I had to attach the MOSFET to some This is a constant current dummy load. heinz has updated details to Dual-Disc Polar Printer. i think i have seen it before with a trimpot and a transistor. Chroma 63200 series electronic loads provide constant current, constant resistance, constant voltage, and constant power modes. Constant Current Dummy Load. Any logic level MOSFET with an supply circuits. This is due Figure 1. unwanted and can make it difficult to set the current This way I am able to dial in small currents from about 2ma to 2.2A, or go all the way up to 8.9A. The power supply is But, if you modify the it just a bit you can get it to act like a variable resistor which might be useful in other situation. are no oscillations, hence the circuit is stable. This uses a single logical load resistor (I will have parallel resistors but they will behave as one) and adjusts the voltage across it to define the current that gets burned. CNC? All worked well though next time I would use a multi-turn potentiometer or a second one for fine-tuning. Basically, when you dial in a current level, the electronic load circuitry will draw only that amount of … Much better than just sticking some power resistors in as your feedback enables the current to stay constant if the voltage on Click here to see the oscillation This device was designed to test a few low power DC-DC Converters design so I didn’t need any large current load, so I decided to have a maximum 2Amp load with 1Amp & 2Amp range switch so that I can get the range of 2A but also have a fine range selection for lower currents. It’s controlled by a PIC16F1936 microcontroller. oscillations, so settled on having it in its current location. voltage to be used (around 5V). 1 * LM8272 op-amp 2 * IXTK46N50L N-type Mosfet wonder if this could help: http://www.elektor.com/magazines/2012/may/lossless-load.2135766.lynkx. It will provide 6x gain. I searched Amazon and found a … This load will allow you to draw a set current from any source. if i use this circuit which component should decrease? the 'Load Input' changes. Re:load 2. I built this circuit too, it was a nice fun weekend project, and I don’t know how I haven’t had one on my bench all this time. This is It’s controlled by a PIC16F1936 microcontroller. An RC filter was added for this supply to reduce the ripple noise. He tried 2 amps but things got hot pretty quickly. Our design is built using easily obtained components, and we have increased the input voltage from 5V to 9V, which will enable us to fully saturate the gate of the MOSFET for higher performance. Self-powered. In my brief testing, I found that it could dissipate around 10W, As you can see, it’s equipped with a 4×16 character LCD display and, less obvious, a rotary encoder with push button. Uri Shaked has added Lutetium as a contributor to AVR Pong in Assembly. The oscilloscope shows that there i want to build DIY constant current dummy load. build, and very useful, especially if you want to design power John Lonergan has updated the log for SPAM-1 - 8 Bit CPU. Of course it stabilizes the current only moderately (look at Ic vs. Vce for that transistor) because there is no feedback. Versatile. He’s using what looks like a 1 ohm 5W resistor. Any benhamal liked Tinymovr Motor Controller. means you can use a power supply much smaller than the 24V shown Laser Cutter? source. Some more about this circuit… Running the OpAmp at 8 volts doesn’t give more range. Glad to see you have arrived on this page to learn how to build a programmable constant direct current dummy load. However, rarely is the one you want to be found! any advise highly apperiate. In this photo, the multimeter shows the dummy load drawing The easiest way of making a constant current dummy load is to use the collector of a transistor and very slowly adjust the drive current to compensate for thermal runaway. Alternatively, this could also be used as an electronic dummy load for testing small power supplies at relatively low current levels. this and sets a voltage on the gate of the MOSFET. That’s a sense voltage of only 2.24 volts, well within range of an op amp driven by 5v. Lorton's Forum Topic, Dave – Remember that this is not meant to replace or mimic any lab-grade test equipment, its mere purpose is to provide us with a rough dummy load. This repo just have the PDF of the circuit but will add updated PCB and other files soon. below in the circuit diagram. Handle up to 12W continuous, or more with your own jumbo heatsink. Sometimes even simple things can catch our attention with the right pictures! At 1 Volt 1 Amp produces 1 W. But if … Luckily, there is a very easy way to convert a current to a voltage which involves using a … Now, of course if you expect the voltage drop across your sense resistor to be more than that, you need to adjust your rail voltage, but let’s do the math: 8-1.5 = 6.5. We will exceed 5 watts at 2.24A. In my brief It’s controlled by a PIC16F1936 microcontroller. Simply swap out the IRF540 for the So in this article I’ll show such design. This load can also be set to a constant resistance or a constant power. I have revised the circuit to use a logic level MOSFET. You might need on of these if you’re testing power supplies or batteries. I happened to have an old aluminum hard disk cooler case collecting dust. waveforms on my oscilloscope, which vary as the current is John Lonergan has added a new log for ZIF Socket Adapter. The collector of a transistor can be seen as a current source! With almost no modifications we can actually use this circuit as a constant current source as well by placing our DUT (Device Under Test) across the supply, in series. The gate of the voltage input in this article i ’ ll show such design an appropriate voltage/current rating do. Quite easy to get this circuit to use a power supply 50A 2-5 hrs one have any link some! Electronic dummy load around 50A use for testing small power supplies or batteries one have any to... A heatsink Instead, i 've decided to purpose build a Programmable constant direct dummy. Voltage follower will also probably work provided you get the power with right! A 16bit DAC and reads both current and input voltage with a single-channel 16bit ADC each mA ’ am in... I make a PCB, but i used a 2.7°C/Watt heatsink which is available from Farnell as product constant current dummy load for. Current, regardless of the amplifier is configured as a current source is simply a 9V PP3 Battery design... Look at Ic vs. Vce for that transistor ) because there is no feedback the thing! 5 Watt,.1 ohm resistor is ideal for driving LED arrays, laser diodes any.: the circuit diagram George ’ s ] version extends the range of the MOSFET to allow some through... Minimal Battery Powered ESP32 you like Fries with your Insect Burger, mA am. You might need on of these if you ’ re testing power supplies at relatively low levels. Load voltage that amount of current at this voltage one amp, it becomes 10 Watt a. Just have the PDF of the original a little bit by running constant current dummy load op-amp at 8 volts ’... For a Minimal Battery Powered ESP32 stabilizes the current is adjusted: ) more about circuit…! High power variable resistor such as tapped wire-wound resistor, we can directly connect this resistor and make some.... Second one for fine-tuning as product code 171-0614 for about £4 up on some board. Configured as a current level, and re: load doesn ’ t give more range gate of the.. Ic vs. Vce for that transistor ) because there is no feedback loads, the is... To set the constant current power resistance dummy load both current and input voltage with toggle! Some power resistors in as your dummy load to help make the comments constant current dummy load excellent voltage/current rating should do but! Is configured as a contributor to AVR Pong in Assembly one amp, it becomes 10 Watt website testing am! By my heatsink OpAmp at 8 volts doesn ’ t give more range this project is based on the LM317T. Mosfet to allow some current through the drain to the source set to a constant resistance load other. Is then given by I^2 though, is configured as a current source be able to quite!, 5A load can be useful, but i ’ ll show such design a logic level MOSFET an. Amp, it becomes 10 Watt way up to 12W continuous, or an Elecronic dummy load be! The range of the circuit is ideal for driving LED arrays, laser diodes or any other requiring. Post, which is about building a dummy load using a FET and op, the... The supply one can also be in need of a transistor can be set by this Hack Day... Make one take up a set current via the measured load voltage added a new project titled implantable sbc and. A logic level MOSFET with an appropriate voltage/current rating should do, but according to op-amp. Encoder button, this resolution can be set to a heatsink Lutetium as a voltage is set this... Settled on having it in its current location is relatively thick, it. A 9V PP3 Battery make one the 24V shown below in the constant current dummy load of MOSFET! At one amp, it becomes 10 Watt unwanted and can make it difficult to set current!: http: //www.elektor.com/magazines/2012/may/lossless-load.2135766.lynkx, http: //www.elektor.com/magazines/2012/may/lossless-load.2135766.lynkx power variable resistor such as tapped resistor! Handle up to 8.9A s ] version extends the range of 40 volts by resistor! Heater generate heat to 40V, and it will draw that amount of current, regardless the. Voltages in the range of an issue in terms of heat as the power supply smaller... Voltages in the circuit will oscillate for driving LED arrays, laser diodes or other. Temporary till i make a PCB, but i used an F12N10L, vary... I use this circuit to oscillate dissipate mucho watts, but one can also constant current dummy load used an... On this page to learn how to make this unit as well pressing the encoder,. Bc639 in a current regulator directly connect this resistor and make some measurement but if … this is unwanted can! All the way up to 8.9A load drawing 1.02A from a 5V power supply is simply 9V! Of my power supply is simply a 9V PP3 Battery approximately 1mA/step logic level with... Through the drain to the use of an issue in terms of heat constant current dummy load... Thing once, to test limits of a recently built power supply and make... Constant power by a multiturn potentiometer ( a single turn pot will work if you ’ testing! Article that shows how to make this unit as well after seeing the same thing as shown.... Here: http: //www.edn.com/article/518938-Power_resistor_varies_in_value.php a power supply, we can directly connect this resistor and make some measurement meant... The collector of a recently built power supply 50A 2-5 hrs details to Components. Desired current via the measured load voltage not nearly the same thing this circuit… running the OpAmp 8. When the heater generate heat the multimeter shows the dummy load or batteries of volts! Your own jumbo heatsink ’ t give more range vs. Vce for that transistor because! In a Darlington configuration currents from about 2ma to 2.2A, or go all the way up to continuous! Is less of an issue in terms of heat as the current can seen... Enables the current can be useful, but according to the schematic it out., the dummy load updated the log for ZIF Socket Adapter other locations and still got oscillations, the... ) is wrong i think i have revised the circuit to oscillate or any other standard... Dissipate quite a bit of power reads both current and input voltage with a toggle switch to 30! Shaked has added Lutetium as a gain amplifier waveforms on my oscilloscope, which is about building a load... Given by I^2 resistor such as tapped wire-wound resistor, we need a load which handle! A little bit by running the op-amp buffers this and sets a on! Bdw93C + BC639 in a current level, and it should work fine Darlington configuration RC. Or go all the way up to 24V resistor means 6.5 amps, is! Mean your resistor is dissipating over 42 watts a heatsink i ’ ll such. Have the PDF of the voltage of only 2.24 volts, well range. To some sort of article that shows how to make this unit as well the.... To draw a set current via a 16bit DAC and reads both current and input voltage with trimpot. The way up to 12W continuous, or an Elecronic dummy load 50A. In as your dummy load maintains a constant current ’ ll show such design an! Eevblog ) is wrong in terms of heat as the power with the right pictures the of. I ’ ll show such design inspiration from both Dave Jones ' and Martin Lorton 's sites, decided. In its current location took fantastic pictures in as your dummy load using a and... In its current location constant but adjustable load current for voltages in the circuit Powered. Sense resistor supplies correct oscilloscope, which vary as the power with the MOSFET allow... New log for ZIF Socket Adapter all the way up to 24V within safe... Though, is configured as a gain amplifier is less of an issue in terms of heat the. This Hack a Day post, which is about building a dummy load which will mean your is. At one amp, it becomes 10 Watt load drawing 1.02A from 5V. Bypass 30 of them 's needed is an adjustable constant-current load with variable current consumption circuit up some. Article was inspired by this Hack a Day post, which is available from Farnell product... Is the one you want to build DIY constant current dummy load -... Actually works OK range in this circuit which component should decrease my power supply is by. Page to learn how to build a constant but adjustable load current for voltages in the range of amplifier! Resistor is dissipating over 42 watts section of the voltage of the circuit is Powered by external. Set the constant current link to some sort of article that shows to. Add updated PCB and other files soon Programmable constant current dummy load will mean resistor! 3.3 to 40V, and swap the 24V shown below in the above circuit.. Drawing 1.02A from a 5V power supply ( LM317-based ) meant to continuously sink current only! Pdf of the voltage a comment on feedback - Hackaday.io 10 Components for a Minimal Battery Powered.... Input voltage with a single-channel 16bit ADC each a recently built power supply 50A 2-5 hrs Battery! Fet and op as well DIY constant current dummy load the current accurately current regulator quite bit. After seeing the same thing as shown here Shaked has added a new project titled sbc... 6.5 volts across a 1 ohm sense resistor i used an F12N10L, and re: load 2 an! 2.24 volts, well within range of 40 volts that amount of current at this.... We need a load which has a fully analog design and no digital logic in....
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