This is the best /easiest to follow video on a basic dummy load , I don't understand why some of youtubers choose to over explain things and inadvertently confuse viewers more than they could imagine , you on the other hand, stick with the simple design and your whole focus is that particular dummy load, I just loved watching it.
Great video. Its basic and yes it leaves room for improvement, but its cheap easy to make and covers 75% of use cases. Just what the budding electronics hobbies needs
With most resistor manufacturers, that specific type of resistor, (i.e. the aluminum housed type), is only rated for its stated wattage on a continuous basis if and *only if* it is mounted to an appropriately sized heatsink in order to keep its temperature from going into "thermal runaway", which will eventually burn up the element inside it... That's the main reason they have the mounting tabs on them along with that one flat side, (the bottom)... Therefore I definitely would recommend using an aluminum box that can dissipate the heat better, and/or mounting the resistors to a larger finned heatsink, like many amplifiers have on them, and/or using a fan to cool them... I also generally, as a "rule of thumb", only run a maximum of half (50%) of the rated wattage of a resistor through it on a continuous basis in order to keep it much cooler and more stable and reliable long term.
Those resistors REALLY need an effective heat sink attached to deliver their power dissipation level. That is why they even have the mounting capability. Mounting them in a plastic box is a recipe for disaster. Smelly melting plastic or even a fire is possible.
Better to build inside a metal test box with a good size heatsink, and thermal paste on resistors. Power resistors on a plastic box, well will melt. Best to invest in a basic setup.
Much appreciate all of those great videos. Wondering if you could somewhat present ideas about frequency counters. I have a few digital ones but don't know where/how to plug in my (superheterodyne) radio to see (exact) frequency I am listening to. Thanks a bunch.
I need something like this to test variable voltage power supplies at 5/10/15/20/25/35 amps, what would I need for these loads? The mains are 120VAC. Would 288w be appropriate for the 35A PS?
Thanks a million mate. What would you suggest for load testing a 12v 8ah battery? Or would this actually work as is. My idea is just to test and see if the battery keeps its charge or has gone bad. Thanks
I want to know how it will work on testing a 12 v/dc 7 Amp per hour battery. This battery is being charged at 1.7 AMPS And also need to run at least 7 amps for a whole hour , so I want to build a quick tester with a load but not sure where to start. I Have done my calculations . I thought of using led lights maybe resistors that help with indicating the percentage of my battery quality ?
no, the power resistor must be mounted on a better surface like alumunium heatsink and some fan for better stability temp. definitely not plastic box, just no
Absolutely correct. If you apply anywhere near 200 watts to those resistors the box will melt. The resistors inside those aluminum housings are actually 10 watt rated in free air. You need an almost infinite heat sink to run them at 50 watts each.
Can you build something like that with a built-in double AA parallel battery holder which connects to the resistor ? Circuit is completed through an external series connected unknown resistive load which can be very low (milli ohms). The box includes measuring points for voltage across 8 ohm or other standard resistor and you will also measure volts across unknown. Ratio of voltages equals ratio of resistance values so you can easily find the unknown For example on a pair of battery jumper leads I measure 8.4 mV and across 4.7 ohm standard resistor in series 1242 mV whence I determine resistance of the jumper lead pair as 31.8 milli ohms.
Hello! I'm using a passive resistive loadbox which is connected to the 8 ohm speaker output of a 100wt guitar amplifier. The loadbox also acts as a passive DI with a built-in level volume pot. I'm unsure if the this passive box is outputting enough signal(either via balanced line(XLR) or unbalanced instrument(1/4" TS )) Is there anyway to test this with a DMM? Thanks!!
60 watt light bulb has no heat with out current, the longer it is on in a confined space the hotter that space will become. So at what point does a non ventilated plastic box melt, or the bulb burst.
Hi master i want make 500 load tester by this type of resistance can you help me how to calculate for 50 risestance each risestance taken 10amps 0.1 R to 100 k and 1w to 100w power of resistance available on market so wich I select
Hi, I want to make a lipo discharge unit but I have an idea about the calculation of the resistance. 4S 5200mAh lipo battery pulling 10 amps to 50% storage level you want to download. What resistance should I use for this? Is it possible to be home made?
Hello, Please, could you explain what is the difference between 8 ohm 50 watts and 16 ohm 50 watts because the 50 watt are the same? Only the ohm's are different. Why can not use resistors just 8 ohm or just 16 ohm for resistive load tester? Thank you very much for sharing!
The wattage rating is how much power they can safely dissipate. If we attached a 12v source to the 8ohm resistor (with no other load) it would draw 1.5A (12/8) which is 18 watts (1.5*12) - it may get warm but is safe. If we wanted to test a 24v source the same 8ohm resistor would draw 72 watts and get very hot and possibly smoke as this is over 50 watts. 24v across 16ohm is only 36 watts which is safe again. Connecting the resistors in series or parallel as he explains in the video allows other combinations and more watts to be safely dissipated.
Great videos! For how long you can overload a 100Watt resistor with for example 20Watt, so totall 120Watt. It is difficult to believe they damage in a few seconds?
This is the best /easiest to follow video on a basic dummy load , I don't understand why some of youtubers choose to over explain things and inadvertently confuse viewers more than they could imagine , you on the other hand, stick with the simple design and your whole focus is that particular dummy load, I just loved watching it.
Great video. Its basic and yes it leaves room for improvement, but its cheap easy to make and covers 75% of use cases. Just what the budding electronics hobbies needs
With most resistor manufacturers, that specific type of resistor, (i.e. the aluminum housed type), is only rated for its stated wattage on a continuous basis if and *only if* it is mounted to an appropriately sized heatsink in order to keep its temperature from going into "thermal runaway", which will eventually burn up the element inside it... That's the main reason they have the mounting tabs on them along with that one flat side, (the bottom)... Therefore I definitely would recommend using an aluminum box that can dissipate the heat better, and/or mounting the resistors to a larger finned heatsink, like many amplifiers have on them, and/or using a fan to cool them... I also generally, as a "rule of thumb", only run a maximum of half (50%) of the rated wattage of a resistor through it on a continuous basis in order to keep it much cooler and more stable and reliable long term.
Those resistors REALLY need an effective heat sink attached to deliver their power dissipation level. That is why they even have the mounting capability. Mounting them in a plastic box is a recipe for disaster. Smelly melting plastic or even a fire is possible.
THANK YOU SO MUCH FOR ELECTRONIC/ELECTRICAL EDUCATIONAL . IT'S VERY EASY AND UNDERSTANDING DETAILS .
Better to build inside a metal test box with a good size heatsink, and thermal paste on resistors. Power resistors on a plastic box, well will melt. Best to invest in a basic setup.
This channel is fantastic, thank you
Much appreciate all of those great videos. Wondering if you could somewhat present ideas about frequency counters. I have a few digital ones but don't know where/how to plug in my (superheterodyne) radio to see (exact) frequency I am listening to. Thanks a bunch.
I need something like this to test variable voltage power supplies at 5/10/15/20/25/35 amps, what would I need for these loads? The mains are 120VAC. Would 288w be appropriate for the 35A PS?
Thanks a million mate. What would you suggest for load testing a 12v 8ah battery? Or would this actually work as is. My idea is just to test and see if the battery keeps its charge or has gone bad. Thanks
the best dummy load is a hot water thank , it can give you 8000w or more and even heat you water at same time .
hahaha
I want to know how it will work on testing a 12 v/dc 7 Amp per hour battery.
This battery is being charged at 1.7 AMPS
And also need to run at least 7 amps for a whole hour , so I want to build a quick tester with a load but not sure where to start. I Have done my calculations .
I thought of using led lights maybe resistors that help with indicating the percentage of my battery quality ?
no, the power resistor must be mounted on a better surface like alumunium heatsink and some fan for better stability temp. definitely not plastic box, just no
Absolutely correct. If you apply anywhere near 200 watts to those resistors the box will melt. The resistors inside those aluminum housings are actually 10 watt rated in free air. You need an almost infinite heat sink to run them at 50 watts each.
One question how could one incorporate this to use for like automotive applications I use a halgon light for load testing a circuit
Can you build something like that with a built-in double AA parallel battery holder which connects to the resistor ? Circuit is completed through an external series connected unknown resistive load which can be very low (milli ohms). The box includes measuring points for voltage across 8 ohm or other standard resistor and you will also measure volts across unknown. Ratio of voltages equals ratio of resistance values so you can easily find the unknown For example on a pair of battery jumper leads I measure 8.4 mV and across 4.7 ohm standard resistor in series 1242 mV whence I determine resistance of the jumper lead pair as 31.8 milli ohms.
Does exist any rule saying Watt power for resistors vs amp power. Just 1:1 so if amp is 40 W@8ohm means 50 Watt resistor ??
Coming for the proyect ....
stayed for the voice
What a compliment :) Thank you
Thanks
Hello! I'm using a passive resistive loadbox which is connected to the 8 ohm speaker output of a 100wt guitar amplifier. The loadbox also acts as a passive DI with a built-in level volume pot.
I'm unsure if the this passive box is outputting enough signal(either via balanced line(XLR) or unbalanced instrument(1/4" TS )) Is there anyway to test this with a DMM? Thanks!!
60 watt light bulb has no heat with out current, the longer it is on in a confined space the hotter that space will become. So at what point does a non ventilated plastic box melt, or the bulb burst.
Hi master i want make 500 load tester by this type of resistance can you help me how to calculate for 50 risestance each risestance taken 10amps
0.1 R to 100 k and 1w to 100w power of resistance available on market so wich I select
Hi,
I want to make a lipo discharge unit but I have an idea about the calculation of the resistance. 4S 5200mAh lipo battery pulling 10 amps to 50% storage level you want to download. What resistance should I use for this? Is it possible to be home made?
Fantastic video, just subbed, your video are well edited and too the point!!
Helpful !
Great Vid. Can you do one of building a 12 car battery load tester of say 100 amps and voltage reading to confirm good battery? Thanks
You can but use a adjustable carbon pile for load with a fan.
Hello,
Please, could you explain what is the difference between 8 ohm 50 watts and 16 ohm 50 watts because the 50 watt are the same? Only the ohm's are different. Why can not use resistors just 8 ohm or just 16 ohm for resistive load tester? Thank you very much for sharing!
The wattage rating is how much power they can safely dissipate. If we attached a 12v source to the 8ohm resistor (with no other load) it would draw 1.5A (12/8) which is 18 watts (1.5*12) - it may get warm but is safe. If we wanted to test a 24v source the same 8ohm resistor would draw 72 watts and get very hot and possibly smoke as this is over 50 watts. 24v across 16ohm is only 36 watts which is safe again.
Connecting the resistors in series or parallel as he explains in the video allows other combinations and more watts to be safely dissipated.
Thank you!
Where's the *Schematic* ?
Great videos!
For how long you can overload a 100Watt resistor with for example 20Watt, so totall 120Watt. It is difficult to believe they damage in a few seconds?