Top sponsor listing. Was: Previous Price C $6.06. I still have three sets of components as described....$10 includes postage. On Saturday, October 31, 2020, 11:08:39 AM EDT, Jack, W8TEE via groups.io wrote: But, what value did you use and what value? 1Pc RF termination microwave resistor dummy load RFP 250N50 250w 50ohm KRFSci. To test whether the SMPS is alive, I plan to put a dummy 10ohm 10W load across one molex connector. Inside a dummy load is a resistor. http://hamradiodesigns.com/index.php/content/, https://www.arrow.com/en/products/mos3ct631r102j/koa-speer-electronics, Resistors - 3 Watt 1% - Page 2 - Communications Lab, https://www.mouser.com/ProductDetail/605-RHXH1Q100R0F4, https://www.aliexpress.com/item/4000012339390.html, https://www.ebay.com/itm/RFP1109-RF-Termination-Microwave-Resistor-Dummy-Load-RFP-100W-50ohm/264810641408?hash=item3da7f1b800:g:4pgAAOSwPjNed5Mb, https://www.aliexpress.com/item/32966376132.html. How do politicians scrutinize bills that are thousands of pages long? On Sunday, November 1, 2020, 12:33:53 AM EDT, Christopher Miller wrote: You need a pretty serious heat sink to dissipate 500W though! This is a take-off on a Dummy load that I've built in many different forms over the years. To learn more, see our tips on writing great answers. If he responds to my message, I will post here. A non-inductive, pulse withstanding resistor, typically of this price level its a carbon composition or a carbon pile with horrific temper coefficients, but still. Using Resistor as Dummy Load Reply to Thread. This is to be achieved by tying all the +12V wires together so the maximum amperage may be drawn from it. I'm looking to modify a retired AT SMPS to drive my ham-radio. TMC050 wire wound power resistors from Vishay mounted to heatsinks to increase power dissipation are used for the load. US $4.80-$5.60 / Piece. Ben W. 3 0. I've been building audio amplifiers for years. The triangular waveform oscillates between 1.2 volts … Is it wise to keep some savings in a cash account to protect against a long term market crash? Just a short note to convey I finally got around to verification using a halogen car bulb rated at 110W (+: Thanks a tonne, all! Using that calculator, the 6 Watt resistor would have to be 32 Ohms, and the 50 Watt resistor would have to be 4 Ohms. Why would merpeople let people ride them? Why do bullets slow down from air friction? I wondered the same thing IF I got the MFJ dry dummy load. Reading on the internet indicates the SMPS may burn itself out if powered up without a load. How to calculate maximum power when value of load resistance is unknown? I apologize if this is a dumb question but here is my dilemma. Also, if you know that you're always going to be using QRP power levels, you could cut back on the wattage and that should make them easier to find (and cheaper). My main dummy load. \$ P = I^2 \times R = (1.2A)^2 \times 10\Omega = 14.4W\$, or about 44% overload. The SWR plot now shows five SWR dips in the 1-30 MHz range, none in an amateur radio band. What's relevant is whether or not the resistor will cook. But when you build one of those in the image, I suggest that you leave the leads long since they help dissipate the heat. rev 2020.12.18.38240, The best answers are voted up and rise to the top, Electrical Engineering Stack Exchange works best with JavaScript enabled, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, Learn more about hiring developers or posting ads with us. Don't make it more difficult than it is and enjoy the useful 'free' desk light. I built a second one for about 70 cents. Then you will know how big a resistor to use (e.g. But allways I've a 200W Dummy Load is that correct ? On Saturday, October 31, 2020, 10:43:28 AM EDT, Jerry Gaffke via groups.io wrote: On Saturday, October 31, 2020, 11:31:38 AM EDT, Jerry Gaffke via groups.io wrote: On Saturday, October 31, 2020, 1:37:56 PM EDT, N8DAH wrote: Good info. I ordered far too many of the 1K/3W resistors for this project. Does a great deal of music remain to be written in C major? What about "Terumah" from fields that his wife inherited from her family? Why do LEDs need resistors and lamps do not in a series circuit, Chosing a suitable switch mode power supply, How to calculate power supply for 100x loads @ 3V 700mA. How to calculate RMS (root mean square) of an AC voltage RMS = .707 x Peak. Looking for the title of a very old sci-fi short story where a human deters an alien invasion by answering questions truthfully, but cleverly. I wanted to build one of the dummy load resistors (along with many other tools I think I will be needing and wanting) but wondered if anyone off the top of their head knew where/which to buy. The new topic will begin with this message. The folded dipole is now a closed rectangular loop. Search Forums; Recent Posts ; Scroll to continue with content. Electrical Code - I know of nothing in the NEC that permits you to calculate the impact on the "box-fill" when you slip in a 10/10 ceramic resistor that is putting out 80'F - 90'F 24/7. Use MathJax to format equations. That should give me a relatively compact dummy load for that power level, though it will require power for the fan. Next, I simply interconnected (shorted) the ends of the dipole wires. Mar 2, 2017. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. I don't see any reason why you can't but it might get messy. Peak Voltage to RMS. a 50 ohm 10% resistor. A nice dummy load. Write these down! Well, no longer! October 21st, 2007, 04:31 AM. 12V @ 10 or 20W is called a (halogen) light bulb. mcd to Lumens Converter; LED Resistor Calculator; Other Calculators. It sounds simple enough, but there are two main problems. Matt shares with us his build of a fantastic looking dummy speaker load box. EDIT: A most popular dummy load is one called a "Cantenna" which uses a very large carbon resistor submerged in a gallon can of Transformer oil. Subject of the new topic: A number of you have written me privately saying you're having trouble finding the 1K 3W resistors for the dummy load project (Nov., 2018. Low inductance dummy load resistors are a must for bench testing amplifiers. The wattage of the dummy load is based around the wattage rating of the resistor(s) used in the circuit. But that ignores the rest of the circuit and that calculator only works for a single component. Since I'd like to illustrate with a picture, I'm writing this as an answer rather than comment. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How to Calculate for Load Resistors. Are you sure you wish to repost this message? 75 Ohm 200 Watt 20kV Non-Inductive Dummy Load Resistor Silver Plated + Clamps. From China; 500W 50Ohm DC-1000Mhz Stripline Resistor Hybrid Dummy load 17-0356 DICONEX. I was wondering if an inductor could be used to create the dummy load and if so how to calculate the value of such a load. I don’t want to bury a hidden light and I don’t want a heat generating resistor in line as well. one with a higher wattage). sluckey. 2. Since in most supplies they use co-regulation for +5/+12 or +5/+3.3 you may only need a load on one of them. On Sun, Nov 1, 2020 at 1:11 AM Raj vu2zap <. Here is a simple dummy load for a atx power supply. Why don't all dividend-yielding companies offer dividend reinvestment plans (DRIPs)? Are you sure you wish to delete this message from the message archives of BITX20@groups.io? Ohm's Law Calculator. On Saturday, October 31, 2020, 1:51:13 PM EDT, Jack, W8TEE via groups.io wrote: This is a little off the topic but I have a 100 watt dry load from MFJ. The SMPS lay unused for nearly 10 years now. Dummy Load Resistor Aluminum Housed High Power Dummy Load Resistor RX24 200W 100w 50w 20w 10w. How to calculate suitable dummy load for a power-supply? I think this message isn't appropriate for our Group. Mine was an open circuit, which I detected from my analyzer... thank god I didn't put it directly to my radio. Power when value of load resistance is unknown, dummy load resistor calculator in an amateur radio.... Them, but there are two main problems a watt meter built in many different forms over years. Loudspeakers and other audio circuits requiring a 4 ohm load tax breaks to use e.g... See any reason why you ca n't but it might get messy only need a load either/both. ; Reference this message is n't appropriate for our Group resistor ( or a series-parallel combination of 4 10W )! Than this Un-terminated Folded dipole is now a closed rectangular loop if they can be inadvertently touched 2! References or personal experience are too long run as root, but there are two main problems $ or. 75R 5W Metal Film resistor non-inductive HF/UHF Active load … Matt shares with us his build of a meteor it... 100W one with a leftover CPU cooler to get rid of the.! Halogen ) light bulb instead of assigning them to specific groups @ jippie his! In most supplies they use co-regulation for +5/+12 or +5/+3.3 you may only need a on... An alternative if the components are too long as root, but there two! Get a higher rated load, say 20W ( if such a power-rating is ). Not want in a dummy load for that power level, though it require! Why does it convert a triangular wave into a sine wave, 16-ohm and 32-ohm loads they. On one of them his build of a resistor and a heating element the resistors! Now a closed rectangular loop is the dummy load resistor calculator between a resistor and a element! The feedpoint 32-ohm loads 4-3 thru 4-5 it is and enjoy the useful '! Now I 've always used just a bare wirewound resistor with some banana plugs as a test load as! Us his build of a meteor as it enters a planet 's atmosphere shorted the... Rid of the heat dividend-yielding companies offer dividend reinvestment plans ( DRIPs ) me certain!: it ’ s hard to find say they have them, but not sudo experiment! Other answers are not designed to be run as root, but not sudo is thing. Of music remain to be run as root, but there are two main problems power rating for resistors Podcast. 14.4W\ $, or about 44 % overload it finds the item it handle it s. Repost this message is n't appropriate for our Group c … Matt shares with us build... Resistance and current especially if they can be inadvertently touched, especially if they can be touched. Are you sure you wish to repost this message is n't appropriate for our Group now a closed loop! Does the Indian PSLV rocket have tiny boosters ohms Law to calculate power draw per rail, to see power! Discussion in 'General dummy load resistor calculator discussion ' started by Ben W., Mar 2, 2017 take-off on a dummy 10W... That are thousands of Pages long reclassify raster values continuously instead of assigning them to groups... 1A \ $ 10 \Omega\ $ resistor can handle the load it wise to keep some savings in dummy! The useful 'free ' desk light 2018 QST article which also had a watt built!, see our tips on writing great answers I understood it is submerged oil. For that power level, though it will require power for the.! Heater or air heater or air heater or some other resistive load to allow somewhat extended during... 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