Power Transformer: 110V and 220V input, with two 15V outputs 180 degrees out of phase
I have never designed a power supply before and have a few questions and would appreciate any help.
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
Lastly, I cannot find any transformers with these specifications. What I've been looking for is a center tap primary and secondary with a ratio of 15:1
Thank you in advance.
power transformer
add a comment |
I have never designed a power supply before and have a few questions and would appreciate any help.
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
Lastly, I cannot find any transformers with these specifications. What I've been looking for is a center tap primary and secondary with a ratio of 15:1
Thank you in advance.
power transformer
1
Is that 15V AC or DC? And does it need to be isolated?
– ratchet freak
Nov 12 at 12:08
1
A centre tapped transformer CANNOT be rewired as you seem to be implying.
– Andy aka
Nov 12 at 12:34
add a comment |
I have never designed a power supply before and have a few questions and would appreciate any help.
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
Lastly, I cannot find any transformers with these specifications. What I've been looking for is a center tap primary and secondary with a ratio of 15:1
Thank you in advance.
power transformer
I have never designed a power supply before and have a few questions and would appreciate any help.
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
Lastly, I cannot find any transformers with these specifications. What I've been looking for is a center tap primary and secondary with a ratio of 15:1
Thank you in advance.
power transformer
power transformer
edited Nov 12 at 12:50
SamGibson
10.8k41537
10.8k41537
asked Nov 12 at 12:05
Andre Faraday
364
364
1
Is that 15V AC or DC? And does it need to be isolated?
– ratchet freak
Nov 12 at 12:08
1
A centre tapped transformer CANNOT be rewired as you seem to be implying.
– Andy aka
Nov 12 at 12:34
add a comment |
1
Is that 15V AC or DC? And does it need to be isolated?
– ratchet freak
Nov 12 at 12:08
1
A centre tapped transformer CANNOT be rewired as you seem to be implying.
– Andy aka
Nov 12 at 12:34
1
1
Is that 15V AC or DC? And does it need to be isolated?
– ratchet freak
Nov 12 at 12:08
Is that 15V AC or DC? And does it need to be isolated?
– ratchet freak
Nov 12 at 12:08
1
1
A centre tapped transformer CANNOT be rewired as you seem to be implying.
– Andy aka
Nov 12 at 12:34
A centre tapped transformer CANNOT be rewired as you seem to be implying.
– Andy aka
Nov 12 at 12:34
add a comment |
2 Answers
2
active
oldest
votes
Using a centre-tapped primary usually means that you de-rate the transformer to half power.

Figure 1. Series and parallel connections for split-winding transformer. Image source: Electro-Dan. The linked article discusses torroidal transformers but the principle is the same for standard transformers.
Instead, the common approach due to its flexibility is to use a transformer with two 110 V primaries and two equal secondaries. The primaries can then be wired in series for 220 V operation and parallel for 110 V. Similarly, the secondaries can be wired in parallel for high current or series for higher voltage. The series connection point is, in effect, the secondary centre-tap.

Figure 2. For switching primary voltage by the user you would add a voltage selector switch. Source: Modulus Amplification.
Thank you very much! Helped a lot!
– Andre Faraday
Nov 12 at 14:16
The yellow and blue is not a center tap, they are the ends of two windings. A center tap is continuous through the transformer and cannot be separated.
– Harper
Nov 12 at 19:20
add a comment |
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
The normal approach is to use a transformer that has two identical primary windings, each rated for 110V and half the total transformer power. You put them in parallel for 110V operation and put them in series for 220V operation. This optimizes the amount of copper required.
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
If you ground the center tap, you can use the other two terminals to make separate +15V and -15V supplies. The fact that they are out of phase allows you to use full-wave rectification for both supplies.
Lastly, I cannot find any transformers with these specifications.
That would be a product recommendation, which is off-topic here.
Yeah, and don't attempt to half-wave rectify them unless either your load is balanced or your transformer mount is very sturdy and well dampened :)
– rackandboneman
Nov 12 at 19:43
add a comment |
Your Answer
StackExchange.ifUsing("editor", function ()
return StackExchange.using("mathjaxEditing", function ()
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["\$", "\$"]]);
);
);
, "mathjax-editing");
StackExchange.ifUsing("editor", function ()
return StackExchange.using("schematics", function ()
StackExchange.schematics.init();
);
, "cicuitlab");
StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "135"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);
else
createEditor();
);
function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);
);
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2felectronics.stackexchange.com%2fquestions%2f406324%2fpower-transformer-110v-and-220v-input-with-two-15v-outputs-180-degrees-out-of%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Using a centre-tapped primary usually means that you de-rate the transformer to half power.

Figure 1. Series and parallel connections for split-winding transformer. Image source: Electro-Dan. The linked article discusses torroidal transformers but the principle is the same for standard transformers.
Instead, the common approach due to its flexibility is to use a transformer with two 110 V primaries and two equal secondaries. The primaries can then be wired in series for 220 V operation and parallel for 110 V. Similarly, the secondaries can be wired in parallel for high current or series for higher voltage. The series connection point is, in effect, the secondary centre-tap.

Figure 2. For switching primary voltage by the user you would add a voltage selector switch. Source: Modulus Amplification.
Thank you very much! Helped a lot!
– Andre Faraday
Nov 12 at 14:16
The yellow and blue is not a center tap, they are the ends of two windings. A center tap is continuous through the transformer and cannot be separated.
– Harper
Nov 12 at 19:20
add a comment |
Using a centre-tapped primary usually means that you de-rate the transformer to half power.

Figure 1. Series and parallel connections for split-winding transformer. Image source: Electro-Dan. The linked article discusses torroidal transformers but the principle is the same for standard transformers.
Instead, the common approach due to its flexibility is to use a transformer with two 110 V primaries and two equal secondaries. The primaries can then be wired in series for 220 V operation and parallel for 110 V. Similarly, the secondaries can be wired in parallel for high current or series for higher voltage. The series connection point is, in effect, the secondary centre-tap.

Figure 2. For switching primary voltage by the user you would add a voltage selector switch. Source: Modulus Amplification.
Thank you very much! Helped a lot!
– Andre Faraday
Nov 12 at 14:16
The yellow and blue is not a center tap, they are the ends of two windings. A center tap is continuous through the transformer and cannot be separated.
– Harper
Nov 12 at 19:20
add a comment |
Using a centre-tapped primary usually means that you de-rate the transformer to half power.

Figure 1. Series and parallel connections for split-winding transformer. Image source: Electro-Dan. The linked article discusses torroidal transformers but the principle is the same for standard transformers.
Instead, the common approach due to its flexibility is to use a transformer with two 110 V primaries and two equal secondaries. The primaries can then be wired in series for 220 V operation and parallel for 110 V. Similarly, the secondaries can be wired in parallel for high current or series for higher voltage. The series connection point is, in effect, the secondary centre-tap.

Figure 2. For switching primary voltage by the user you would add a voltage selector switch. Source: Modulus Amplification.
Using a centre-tapped primary usually means that you de-rate the transformer to half power.

Figure 1. Series and parallel connections for split-winding transformer. Image source: Electro-Dan. The linked article discusses torroidal transformers but the principle is the same for standard transformers.
Instead, the common approach due to its flexibility is to use a transformer with two 110 V primaries and two equal secondaries. The primaries can then be wired in series for 220 V operation and parallel for 110 V. Similarly, the secondaries can be wired in parallel for high current or series for higher voltage. The series connection point is, in effect, the secondary centre-tap.

Figure 2. For switching primary voltage by the user you would add a voltage selector switch. Source: Modulus Amplification.
answered Nov 12 at 12:33
Transistor
80.2k778173
80.2k778173
Thank you very much! Helped a lot!
– Andre Faraday
Nov 12 at 14:16
The yellow and blue is not a center tap, they are the ends of two windings. A center tap is continuous through the transformer and cannot be separated.
– Harper
Nov 12 at 19:20
add a comment |
Thank you very much! Helped a lot!
– Andre Faraday
Nov 12 at 14:16
The yellow and blue is not a center tap, they are the ends of two windings. A center tap is continuous through the transformer and cannot be separated.
– Harper
Nov 12 at 19:20
Thank you very much! Helped a lot!
– Andre Faraday
Nov 12 at 14:16
Thank you very much! Helped a lot!
– Andre Faraday
Nov 12 at 14:16
The yellow and blue is not a center tap, they are the ends of two windings. A center tap is continuous through the transformer and cannot be separated.
– Harper
Nov 12 at 19:20
The yellow and blue is not a center tap, they are the ends of two windings. A center tap is continuous through the transformer and cannot be separated.
– Harper
Nov 12 at 19:20
add a comment |
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
The normal approach is to use a transformer that has two identical primary windings, each rated for 110V and half the total transformer power. You put them in parallel for 110V operation and put them in series for 220V operation. This optimizes the amount of copper required.
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
If you ground the center tap, you can use the other two terminals to make separate +15V and -15V supplies. The fact that they are out of phase allows you to use full-wave rectification for both supplies.
Lastly, I cannot find any transformers with these specifications.
That would be a product recommendation, which is off-topic here.
Yeah, and don't attempt to half-wave rectify them unless either your load is balanced or your transformer mount is very sturdy and well dampened :)
– rackandboneman
Nov 12 at 19:43
add a comment |
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
The normal approach is to use a transformer that has two identical primary windings, each rated for 110V and half the total transformer power. You put them in parallel for 110V operation and put them in series for 220V operation. This optimizes the amount of copper required.
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
If you ground the center tap, you can use the other two terminals to make separate +15V and -15V supplies. The fact that they are out of phase allows you to use full-wave rectification for both supplies.
Lastly, I cannot find any transformers with these specifications.
That would be a product recommendation, which is off-topic here.
Yeah, and don't attempt to half-wave rectify them unless either your load is balanced or your transformer mount is very sturdy and well dampened :)
– rackandboneman
Nov 12 at 19:43
add a comment |
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
The normal approach is to use a transformer that has two identical primary windings, each rated for 110V and half the total transformer power. You put them in parallel for 110V operation and put them in series for 220V operation. This optimizes the amount of copper required.
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
If you ground the center tap, you can use the other two terminals to make separate +15V and -15V supplies. The fact that they are out of phase allows you to use full-wave rectification for both supplies.
Lastly, I cannot find any transformers with these specifications.
That would be a product recommendation, which is off-topic here.
Firstly, I want to use a transformer that can both take 220V and 110V inputs. Can I use a center tap transformer and for 110V put the coils in series and for 220V only use one coil and leave the second open circuited?
The normal approach is to use a transformer that has two identical primary windings, each rated for 110V and half the total transformer power. You put them in parallel for 110V operation and put them in series for 220V operation. This optimizes the amount of copper required.
Secondly, I need an output of + and - 15, so do I select a transformer with a center tap secondary and wire the two identical outputs to be 180 degrees out of phase?
If you ground the center tap, you can use the other two terminals to make separate +15V and -15V supplies. The fact that they are out of phase allows you to use full-wave rectification for both supplies.
Lastly, I cannot find any transformers with these specifications.
That would be a product recommendation, which is off-topic here.
answered Nov 12 at 12:34
Dave Tweed♦
117k9144256
117k9144256
Yeah, and don't attempt to half-wave rectify them unless either your load is balanced or your transformer mount is very sturdy and well dampened :)
– rackandboneman
Nov 12 at 19:43
add a comment |
Yeah, and don't attempt to half-wave rectify them unless either your load is balanced or your transformer mount is very sturdy and well dampened :)
– rackandboneman
Nov 12 at 19:43
Yeah, and don't attempt to half-wave rectify them unless either your load is balanced or your transformer mount is very sturdy and well dampened :)
– rackandboneman
Nov 12 at 19:43
Yeah, and don't attempt to half-wave rectify them unless either your load is balanced or your transformer mount is very sturdy and well dampened :)
– rackandboneman
Nov 12 at 19:43
add a comment |
Thanks for contributing an answer to Electrical Engineering Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2felectronics.stackexchange.com%2fquestions%2f406324%2fpower-transformer-110v-and-220v-input-with-two-15v-outputs-180-degrees-out-of%23new-answer', 'question_page');
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
Is that 15V AC or DC? And does it need to be isolated?
– ratchet freak
Nov 12 at 12:08
1
A centre tapped transformer CANNOT be rewired as you seem to be implying.
– Andy aka
Nov 12 at 12:34