I like your tutorial video and all your feedback comments.easy to understand.its really helpfull for me and many people.keep it up and thanks a lot sir.
You can measure the resistance from each transformer wire to the case or core of the transformer. You should get an infinite resistance measurement if all is okay.
Thank you, the turns ratio formula at about minute 2.40 will help me determine the size fuse I need for a (120V to) 14 volt 1.1 amp transformer for a little lamp I am trying to fix.
I have a transformer in my air handler with 240v input but has a 31,15v output under load. It’s supposed to be 24v. Would this or could this cause my 5a fuse to blow? It’s basically 7.15v too high.
But wouldn’t the fuse protect your ❤️ from taking too much amperage acrosst it? And btw, you have many plastic power apparatus with bolt in transformers where your at? Can’t say I ever saw one here..... 😆. I enjoyed your video! Just heckling.. 👍🏼&subbed
i bought a Weller soldering station from Amazon that uses a 110v input but i live in UAE where the mains power supply is 230v, any idea how to work it without damaging it..!! jazakom Allah
if the trans is rated for 2amps the fuse also needs to be 2amps? i think i used a 4amp fuse instead, also it says 12 volt 2amp for the outer wires but there is a yellow/green wire in between them ,would that be for 6v and 4 amps instead? it basically says " grn-grn/yel-grn:12vct 2a" does this mean any connection will give 12 volts or is this still a center tap wire?
I have read that by step-down transformers the voltage goes down and the current goes up. Why is by these transformers the current so small (0,2 A; 0,5 A)? What are they used for? What does depend on, whether the maximal current is 0,2 A or 2 A? On the size of the transformer? More wire on both sides for more amps? Thanks for the interesting video.
+Stephan1098 It all depends on the power rating or volt amps (VA) of the transformers. The transformers I used in the video are all rectifying transformers used for DC power supplies. Here is a simplified explanation. The turns ratio (a) = primary voltage (Vp) / secondary voltage (Vs) = secondary current (Is) / primary current (Ip). The volt amp (VA) rating = Vp x Ip = Vs x Is (assuming no loss).
Stephan1098 I guess the bigger size is due to the use of thick wire to reduce resistance or increase current sir how would u know Ip ? Can I assume 5amps as 5 amp 230 volts is supplied to house? or it depends on load so as to maintain required current for the load?
Yes, the bigger the wire the less resistance resulting in a bigger transformer. If you have a 5 amp transformer this would be the maximum current the transformer can handle on the winding the 5 amps marking was taken from. The load that is attached to the secondary winding decides (over simplified) the current flow.
I have several transformers that I have picked up over the years.Most are from microwave ovens but a few are smaller or larger and the sources are long forgotten. The other night I decided to test them to see what the output voltages are and even though they may say 120v and 60hz when I plug them in using an old cord and an outlet on my work bench, they pop my work bench breaker! They may have anywhere from 2-6 wires coming off the secondary, none touching, and only 2 wires on the primary, but when I plug it in POP ! Any ideas? Thx
Very well explained sir. Transformer in my speaker got burnt may be due to high voltage. Replaced it with the help of your video and attached a fuse as well to it. Thank you. I have a query. The transformer input voltage is 230V (India) and output is 12V-0V-12V / 1 Amp. What should be reading for fuse.? As of now, the fuse which I have inserted has 3A/250V written on it. Any suggestions.? I may keep the speakers till you recommend me the fuse.
i too have the exact same step down transformer!!!. i have a question "i intend to use 2 fuses one on each side i.e, on primary side as well as on the secondary side" any advice on what fuse should i use on the secondary side and how to calculate it??
..but what would happen if i reverse the input to output..or power through the secondary..would it be a step up...is it ok to do that...fused on the input.. of course
*Did you know?* Tape can be hazardous to hold down cords! 1: If a fault occurred and it heated up the copper/metal/iron wire or the plastic coating of the wire, it can melt the tape because of its paper material, however, it does not light on fire and turn in to ash. 2: This might sound funny and it is a hose-like situation. Tape has a great performance holding down it’s target. Just like a hose, it can cause a voltage clog. To test, you will need 2 ---.---- digit voltage readers on the left of the center and the right of the center, wire (not bare, or without plastic coating it), and tape. Tape the center area of the wire like it is at 9:56. Then, hold 2 readers on each side of the center. I had 0.06 volts travelling through the wire. Again, like a hose, the tape acts like a foot on a hose, so it clogs a little of the voltage. Start: Left: 0.06kV; Right: 0.04kV (See?). A bit in: Left: 0.11kV, Right: 0.00kV. Do the experiment yourself, but I used a bit tinier wire to test it.
Hello, thank you very much for your video, it was very helpfull ! Where can I get such multimeter probes ? They seem handy with their retractable "hook".
+Bluescobra - The ones I was using in the video came with the Fluke digital multimeter. You should be able to purchase them at any electronic supplier selling electronic test equipment.
it's been a long while and i dont remember all the q's i had but here are a couple for now,, 1)if i have a 12vdc 2amp trans for the outer wires on the output does that mean if i use the center tap instead i would get 6v at 4amp? 2)also what kind of fuse should i be using for this trans,the 2 amp or the 4 amp? does it depend on what wires i want to be using?
The secondary winding is designed in your case only to draw a maximum of 2A, The fuse should be place in the primary winding to properly protect the transformer
is bad that if the resistances between the CT to a secondary coil and between one secondary coil to another is the same? your readings from a secondary coil to CT is aprox half that of one secondary coil to another.
Depending on the quality of your multimeter and the wire gauge of the transformer you should measure approximately the same from the CT to each end of the secondary winding or 1/2 of the total winding resistance.
thanks but still got questions unanswered. when you connect the primary to power arent you causing a short circuit? 110v/15 ohm= about 8A of current flow whichis veryhigh. what am I missing here?
This would be true in a resistive circuit but the transformer also has inductance that complicates things. Remember the load in the secondary circuit controls what happens in the primary side. No load, no current in the primary circuit under ideal and loss less transformer.
Normally the current rating or VA rating will be on the transformer. If it is not marked hopefully there is a part number you can Google to find the information. If none of this information is available it is extremely difficult to determine the power rating of the transformer.
Sounds like the primary winding is defective. The wires used to connect to the power source are soldered to the actual winding wire. Sometimes these wires become disconnected. Since the transformer is not working, carefully cut away the paper protecting the winding and see if you can find the connections.
Most I find have a thermal fuse under the wrap pressed against the windings that has burned out. You can replace or bypass it to make it work again. I recently did a bath fan motor but damn those wires were so small I could barely solder them.
First transformer is 12 volt, and the fourth (big) transformer is 24 volt. so the first transformer's size is almost half than the fourth 2 amp 24 volt transformer.
Winston Vanderbuilt II transformers only exist in AC to AC, if you want to make it DC to DC, you’ll need to make 2 circuits. An DC to AC generator. And a AC to DC rectifier.
Vp/Vs=Is/Ip is the relationship used. Therefore 115v/25v=0.3a/Ip Ip=0.065a (assuming no losses). The secondary maximum current was identified as 0.3 amps, then the maximum primary current or fuse size will be 0.065 amps, again assuming no losses in the transformer.
Make sure your meter is set to measure DC volts first. If the meter reads 0v on the AC voltage function then the transformer is faulty. Another thing you can check is to make sure the transformer has an input voltage.
excuse me sir i have a transformer (step-down) from 220v to 12 volt its output rating is 12v 2 amps i have 3 output wires 12v-GND-12v can i get a 24v from this transformer by any means?
Sounds like the secondary winding has a center tap. One of the wires on the secondary side should have a different colour and the other two will be the same. With power applied to the transformer and using your AC voltmeter, connect one lead of the meter to the odd coloured secondary wire and measure the voltage from this point to each of the other wires, it will be the same. Then measure the voltage across the two wires that have the same colour, it will be twice as much. Now the voltage measurement will be higher than the rated voltage on the transformer as you will be measuring a no-load voltage. Depending on the size of the transformer and where it is made you should measure a no-load voltage across the entire secondary winding somewhere around 26-28vac. The labeling you described, 12v-gnd-12v is a common method used for center tapped transformers with 24v across the entire secondary winding. Good luck.
someone told me if i connected the two 12v lines together to get 12v with 4 amps the transformer will burn and it is wrong to do this is this right or wrong and how to get a 24 volt terminal and a ground terminal from this transformer to be able to rectify them to a dc and build my circuit i know that if i measured the two 12v wires with a multimeter it will give me a 24 v but none of them is a GND both of them is 12v but to rectify this i need a GND terminal as i know. i don't know if i can rectify a two 12v terminals. i am new to transformers this will explain many things to me. and thank you anyway sir
Do not parallel the secondary wires. This will not work. The center tap on the secondary becomes a reference point or circuit ground. Circuit ground is not the same as earth ground.
you mean i can rectify both 12v wires and the circuit will choose one to be a GND and then have my 24v rectified as 24v dc is this mean i will not need to use the GND wire on the transformer
he *was* explaining it. If you don't understand this there are some other great tutorials on electronics basics that you might want to check out. I just started learning about this stuff a few months ago and that's where I started.
I really like this video because it's clear concise and to the point. No nonsense, no fluff, and for that, you get a thumbs up from me. Well done!
good, slow, methodical teaching. easy to understand. thanks very much
THANK YOU! Finally, transformers explained in a straight forward manner!
Thanks for the video. The explanation and illustration is very clear and concise.
I like your tutorial video and all your feedback comments.easy to understand.its really helpfull for me and many people.keep it up and thanks a lot sir.
Excellent presentation, and well done! Thank you!
Thank you. Very nicely explained. You are a good man!
I LIKE YOUR STYLE, "We have the option of doing this two ways, the right way and the WRONG way.
I had to subscribe a little later into the video.
u are great sir.like your tutorial.its easy to understand.
Good Information for non-professional people like me...
Thank you for sharing Sir, very clear!
thanks a bunch for the video and explanation, you are awesome!!!!!
Thanks John, Never to old to learn. I now know a bit more in this regard.
Thank you for sharing Well explained & professional
Very well explained. Thanks, well done
Thank you very much. Greatly explained.
very good information .. I learned a lot
Thanks for the good info! I'm building a project desoldering iron and Hopefully this is a good step in the right direction.
Excellent video and well explained. Thank you
Thanks for such a great video. you are doing really good. keep uploading:-)
Very interesting and easy to follow, thank you. 2016
I woud do measurement all wire of transformer againt case of transformer...isulation...
Best video i see this about topic...thank you very much...
You can measure the resistance from each transformer wire to the case or core of the transformer. You should get an infinite resistance measurement if all is okay.
Very informative, I have some unmarked transformer I need to measure and label for future use. Thank you!
Thank you, the turns ratio formula at about minute 2.40 will help me determine the size fuse I need for a (120V to) 14 volt 1.1 amp transformer for a little lamp I am trying to fix.
great video
goes to show i learn something new every day.thank you very much .)0 ohms = a short in the transformer.That i did not realize.
very useful ! thanks john
very well done.
Well done.
Where can someone either salvage them selves or buy a stepdown transformer to go from 120 volts down to anything between 12.5- 14 volts
clear and consice thank you .. how should you determine fuse size ty joe
I have a transformer in my air handler with 240v input but has a 31,15v output under load. It’s supposed to be 24v. Would this or could this cause my 5a fuse to blow? It’s basically 7.15v too high.
But wouldn’t the fuse protect your ❤️ from taking too much amperage acrosst it?
And btw, you have many plastic power apparatus with bolt in transformers where your at? Can’t say I ever saw one here..... 😆.
I enjoyed your video! Just heckling.. 👍🏼&subbed
i bought a Weller soldering station from Amazon that uses a 110v input but i live in UAE where the mains power supply is 230v, any idea how to work it without damaging it..!! jazakom Allah
if the trans is rated for 2amps the fuse also needs to be 2amps? i think i used a 4amp fuse instead, also it says 12 volt 2amp for the outer wires but there is a yellow/green wire in between them ,would that be for 6v and 4 amps instead? it basically says " grn-grn/yel-grn:12vct 2a" does this mean any connection will give 12 volts or is this still a center tap wire?
if viewer has the electrical gadgets you mentoin . HIGHLY UNLIKELY they would need this video.
I do, and I did.
Just wondering what size fuse you should use to protect the Transformer
On the Hammond 25 volt, I want the full 25v so what so I do with the Green/Yellow striped wire... just cut it off ? Thanks
I have read that by step-down transformers the voltage goes down and the current goes up. Why is by these transformers the current so small (0,2 A; 0,5 A)? What are they used for? What does depend on, whether the maximal current is 0,2 A or 2 A? On the size of the transformer? More wire on both sides for more amps? Thanks for the interesting video.
+Stephan1098
It all depends on the power rating or volt amps (VA) of the transformers. The transformers I used in the video are all rectifying transformers used for DC power supplies.
Here is a simplified explanation.
The turns ratio (a) = primary voltage (Vp) / secondary voltage (Vs) = secondary current (Is) / primary current (Ip).
The volt amp (VA) rating = Vp x Ip = Vs x Is (assuming no loss).
Stephan1098 I guess the bigger size is due to the use of thick wire to reduce resistance or increase current
sir how would u know Ip ?
Can I assume 5amps as 5 amp 230 volts is supplied to house? or it depends on load so as to maintain required current for the load?
Yes, the bigger the wire the less resistance resulting in a bigger transformer.
If you have a 5 amp transformer this would be the maximum current the transformer can handle on the winding the 5 amps marking was taken from. The load that is attached to the secondary winding decides (over simplified) the current flow.
Very good
Was the secondary winding's resistance lower due to wire gauge, or due to shorter total length of conductor in that winding?
For the step down transformers use in this video the secondary winding had a heavier wire used in the winding.
good and perfect
I have several transformers that I have picked up over the years.Most are from microwave ovens but a few are smaller or larger and the sources are long forgotten. The other night I decided to test them to see what the output voltages are and even though they may say 120v and 60hz when I plug them in using an old cord and an outlet on my work bench, they pop my work bench breaker! They may have anywhere from 2-6 wires coming off the secondary, none touching, and only 2 wires on the primary, but when I plug it in POP ! Any ideas? Thx
Very well explained sir. Transformer in my speaker got burnt may be due to high voltage. Replaced it with the help of your video and attached a fuse as well to it. Thank you.
I have a query. The transformer input voltage is 230V (India) and output is 12V-0V-12V / 1 Amp. What should be reading for fuse.? As of now, the fuse which I have inserted has 3A/250V written on it. Any suggestions.? I may keep the speakers till you recommend me the fuse.
3A is too big. Your turns ratio will be 230/24 which is approximately 10. If the secondary is rated at 1 amp then you should use a 0.1 amp fuse.
i too have the exact same step down transformer!!!. i have a question "i intend to use 2 fuses one on each side i.e, on primary side as well as on the secondary side" any advice on what fuse should i use on the secondary side and how to calculate it??
..but what would happen if i reverse the input to output..or power through the secondary..would it be a step up...is it ok to do that...fused on the input.. of course
*Did you know?*
Tape can be hazardous to hold down cords!
1: If a fault occurred and it heated up the copper/metal/iron wire or the plastic coating of the wire, it can melt the tape because of its paper material, however, it does not light on fire and turn in to ash.
2: This might sound funny and it is a hose-like situation. Tape has a great performance holding down it’s target. Just like a hose, it can cause a voltage clog.
To test, you will need 2 ---.---- digit voltage readers on the left of the center and the right of the center, wire (not bare, or without plastic coating it), and tape. Tape the center area of the wire like it is at 9:56. Then, hold 2 readers on each side of the center. I had 0.06 volts travelling through the wire. Again, like a hose, the tape acts like a foot on a hose, so it clogs a little of the voltage. Start: Left: 0.06kV; Right: 0.04kV (See?). A bit in: Left: 0.11kV, Right: 0.00kV. Do the experiment yourself, but I used a bit tinier wire to test it.
but tape is better than nothing. :)
good info.
What is the cy? You said it was 60 cys but what is cycles in a transformer? thanks.
Cycels here means the frequency of the input power., which in US is 60 cycles or Hz and in Europe is 50. Hope this helps.
Hello, thank you very much for your video, it was very helpfull !
Where can I get such multimeter probes ? They seem handy with their retractable "hook".
+Bluescobra - The ones I was using in the video came with the Fluke digital multimeter. You should be able to purchase them at any electronic supplier selling electronic test equipment.
+1929fordhotrod
Thank you!
Gud
sir are you there to reply to some questions?
Yes, I am on the computer more at this time of the year.
it's been a long while and i dont remember all the q's i had but here are a couple for now,,
1)if i have a 12vdc 2amp trans for the outer wires on the output does that mean if i use the center tap instead i would get 6v at 4amp?
2)also what kind of fuse should i be using for this trans,the 2 amp or the 4 amp? does it depend on what wires i want to be using?
The secondary winding is designed in your case only to draw a maximum of 2A, The fuse should be place in the primary winding to properly protect the transformer
as i said it has a center tap,not sure you answered me clearly here,,if you can go over the numbered questions again and answer them,,thank you
is bad that if the resistances between the CT to a secondary coil and between one secondary coil to another is the same?
your readings from a secondary coil to CT is aprox half that of one secondary coil to another.
Depending on the quality of your multimeter and the wire gauge of the transformer you should measure approximately the same from the CT to each end of the secondary winding or 1/2 of the total winding resistance.
thanks but still got questions unanswered. when you connect the primary to power arent you causing a short circuit? 110v/15 ohm= about 8A of current flow whichis veryhigh. what am I missing here?
This would be true in a resistive circuit but the transformer also has inductance that complicates things. Remember the load in the secondary circuit controls what happens in the primary side. No load, no current in the primary circuit under ideal and loss less transformer.
Ozan Saracoglu Inductive reactance. Z. Impedence
good.
1929fordhotrod+ What size fuse should we use for this setup so we can gauge on up and down?
Fuse size depends on the VA rating of the transformer.
sir how can we determine the rating of transformer or output current of it
Normally the current rating or VA rating will be on the transformer. If it is not marked hopefully there is a part number you can Google to find the information. If none of this information is available it is extremely difficult to determine the power rating of the transformer.
hi if a read open on primary wires do I have a bad transformer I'm not getting any reading on ohm setting I do get 1.5 ohms on secondary wires
Sounds like the primary winding is defective. The wires used to connect to the power source are soldered to the actual winding wire. Sometimes these wires become disconnected. Since the transformer is not working, carefully cut away the paper protecting the winding and see if you can find the connections.
Most I find have a thermal fuse under the wrap pressed against the windings that has burned out. You can replace or bypass it to make it work again. I recently did a bath fan motor but damn those wires were so small I could barely solder them.
Lol correct way or incorrect way! I hope that eas a shot @ anyone who dislikes your vids!
First transformer is 12 volt, and the fourth (big) transformer is 24 volt. so the first transformer's size is almost half than the fourth 2 amp 24 volt transformer.
+Moon Mamun - All transformers used in the video where 24v center tapped transformers.
12 volt th-cam.com/video/bvrO7g7BnIA/w-d-xo.html
if my input voltage change will my output voltage change at 12v transformer
Yes, if the input voltage changes the secondary voltage will also change. It is proportional to the transformer turns ratio.
ok thank you sir
How can I step up 0.3 V to 1 v AC voltage? using transformer
we use step up transformer to convert the voltage and after dc we use zenor diode or voltage regulator variable
i have purchased 12-0-12 3 amp transformer when i check this give output me 6 amp.
i have 100 watt audio board which required 12-0-12 3 amp pl hekp
Thanx
what would each of the secondary winding leads read if put to ground?
You should have an infinite reading. None of the transformer wires should have a path to ground.
sorry I meant what voltage (480v prim/ 120v sec side) would I have off the secondary leads to ground
It would be the same as before. No connections of the transformer should have a path to ground therefore an infinite resistance
Forget AC. Please explain DC to DC trnsformers.
Winston Vanderbuilt II transformers only exist in AC to AC, if you want to make it DC to DC, you’ll need to make 2 circuits. An DC to AC generator. And a AC to DC rectifier.
if I understand them correctly the basic stuff is the same, except for polarity. and measuring settings on your multimeter.
i think for safety ppl will plan on removing the power before they remove the fuse anyways
How to test a step down transformers maximum output current?
Maximum current specifications are given by the manufacture of the transformer and cannot be tested.
@@1929fordhotrod what happens if I attach a 1ohm resistor to the secondry coil at 24V? Will 24Amp flow through it or it will get limited?
what is the fuse rating used sir?
Vp/Vs=Is/Ip is the relationship used. Therefore 115v/25v=0.3a/Ip Ip=0.065a (assuming no losses). The secondary maximum current was identified as 0.3 amps, then the maximum primary current or fuse size will be 0.065 amps, again assuming no losses in the transformer.
OK thank you sir
I have a new transformer and 24v is 0 output this is iN HVAC
Make sure your meter is set to measure DC volts first. If the meter reads 0v on the AC voltage function then the transformer is faulty. Another thing you can check is to make sure the transformer has an input voltage.
Well,OFFSHORE mean Chines ? am i right, sir?????????
it means not from the us, mexico or canada.
excuse me sir i have a transformer (step-down) from 220v to 12 volt its output rating is 12v 2 amps i have 3 output wires 12v-GND-12v can i get a 24v from this transformer by any means?
Sounds like the secondary winding has a center tap. One of the wires on the secondary side should have a different colour and the other two will be the same. With power applied to the transformer and using your AC voltmeter, connect one lead of the meter to the odd coloured secondary wire and measure the voltage from this point to each of the other wires, it will be the same. Then measure the voltage across the two wires that have the same colour, it will be twice as much. Now the voltage measurement will be higher than the rated voltage on the transformer as you will be measuring a no-load voltage. Depending on the size of the transformer and where it is made you should measure a no-load voltage across the entire secondary winding somewhere around 26-28vac. The labeling you described, 12v-gnd-12v is a common method used for center tapped transformers with 24v across the entire secondary winding. Good luck.
someone told me if i connected the two 12v lines together to get 12v with 4 amps the transformer will burn and it is wrong to do this is this right or wrong and how to get a 24 volt terminal and a ground terminal from this transformer to be able to rectify them to a dc and build my circuit
i know that if i measured the two 12v wires with a multimeter it will give me a 24 v but none of them is a GND both of them is 12v but to rectify this i need a GND terminal as i know. i don't know if i can rectify a two 12v terminals. i am new to transformers this will explain many things to me.
and thank you anyway sir
Do not parallel the secondary wires. This will not work.
The center tap on the secondary becomes a reference point or circuit ground. Circuit ground is not the same as earth ground.
you mean i can rectify both 12v wires and the circuit will choose one to be a GND and then have my 24v rectified as 24v dc is this mean i will not need to use the GND wire on the transformer
Check out the links below for rectifier circuits
www.tpub.com/neets/book7/0254.GIF
www.interfacebus.com/diode-bridge-split-supply.png
can you explain what your talking about were not all experts
he *was* explaining it. If you don't understand this there are some other great tutorials on electronics basics that you might want to check out. I just started learning about this stuff a few months ago and that's where I started.