electronics question
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PJ Arends wrote:
Does DC power flow from positive to negative
Yes. That is typically how it is diagrammed. There's something odd though about your diagram. The diode just above the limit switch while it is directionally set the same as the one closest to it, if you follow the line from it's base when the limit switch is closed, it flows all the way back to the negative pole. I don't understand the reason for that. :confused:
Chris Meech I am Canadian. [heard in a local bar] In theory there is no difference between theory and practice. In practice there is. [Yogi Berra] posting about Crystal Reports here is like discussing gay marriage on a catholic church’s website.[Nishant Sivakumar]
Chris Meech wrote:
There's something odd though about your diagram. The diode just above the limit switch while it is directionally set the same as the one closest to it, if you follow the line from it's base when the limit switch is closed, it flows all the way back to the negative pole.
Actually it doesn't. If the limit switch is closed it is supposed to keep the two relays on the rightleft activated.
You may be right I may be crazy -- Billy Joel -- Within you lies the power for good - Use it!
modified on Friday, March 25, 2011 12:03 PM
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PJ Arends wrote:
Does DC power flow from positive to negative
Yes. That is typically how it is diagrammed. There's something odd though about your diagram. The diode just above the limit switch while it is directionally set the same as the one closest to it, if you follow the line from it's base when the limit switch is closed, it flows all the way back to the negative pole. I don't understand the reason for that. :confused:
Chris Meech I am Canadian. [heard in a local bar] In theory there is no difference between theory and practice. In practice there is. [Yogi Berra] posting about Crystal Reports here is like discussing gay marriage on a catholic church’s website.[Nishant Sivakumar]
Chris Meech wrote:
diagrammed
X|
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Chris Meech wrote:
diagrammed
X|
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Transistors wold do it. Big ones. (Or valves if you really want to get funky!) Oddly, since electricity is he flow of electrons, they actually flow from negative to positive, repulsion and attraction...
"If climate has not "tipped" in over 4 billion years it's not going to tip now due to mankind." Richard S. Lindzen, Atmospheric Physicist, IPCC "It does not matter who you are, or how smart you are, or what title you have, or how many of you here are, and certainly not how many papers your side has published, if your prediction is wrong then your hypothesis is wrong. Period." Professor Richard Feynman
Correct, but conventional flow (the kind they teach in electrical engineering courses) is from positive to negative, which is the direction of the "arrow" in diode and transstor diagrams. Also, to be even more pedantic, "hole" flow is the flow of positive charge carriers, and so is the flow of positive ions in water.
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Correct, but conventional flow (the kind they teach in electrical engineering courses) is from positive to negative, which is the direction of the "arrow" in diode and transstor diagrams. Also, to be even more pedantic, "hole" flow is the flow of positive charge carriers, and so is the flow of positive ions in water.
Rick Shaub wrote:
"hole" flow
I have to fight so hard not to comment on that. I'll content myself with quoting from an email from a young lady who works here (and cannot spell) when commenting on some changes she had been testing; "I like it on the hole".
Every man can tell how many goats or sheep he possesses, but not how many friends.
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For those who are electronically inclined: http://www3.telus.net/pja/circuit.png[^] I was wondering if there was a way to replace the three internal relays with something else in order to make the circuit solid state. I know that a normally open relay can be replaced with a transistor, but what about a normally closed one? Is there a component that will break a circuit when power is applied to it? Similar to a transistor but with the opposite effect. Also, do I have my diodes in the correct direction? Does DC power flow from positive to negative or the othe other way around? Thanks
You may be right I may be crazy -- Billy Joel -- Within you lies the power for good - Use it!
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Chris Meech wrote:
diagrammed
X|
That is it's transitive verb form. How does that make you unwelled? ;P
Chris Meech I am Canadian. [heard in a local bar] In theory there is no difference between theory and practice. In practice there is. [Yogi Berra] posting about Crystal Reports here is like discussing gay marriage on a catholic church’s website.[Nishant Sivakumar]
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For those who are electronically inclined: http://www3.telus.net/pja/circuit.png[^] I was wondering if there was a way to replace the three internal relays with something else in order to make the circuit solid state. I know that a normally open relay can be replaced with a transistor, but what about a normally closed one? Is there a component that will break a circuit when power is applied to it? Similar to a transistor but with the opposite effect. Also, do I have my diodes in the correct direction? Does DC power flow from positive to negative or the othe other way around? Thanks
You may be right I may be crazy -- Billy Joel -- Within you lies the power for good - Use it!
FET transistors can replace relays in a dc circuit by properly biasing them. I haven't kept up with current parts, but even 20 years ago they were handling 100A loads. I'm sure they can do better today. The nice thing about FETs is that the gate terminal draws near zero current, so it's easy to set switching thresholds using a simple resistor divider. I can't look too closely at the circuit right now, as my employer actually expects me to work on job related stuff while I'm here, but I'll take another look tonight.
Will Rogers never met me.
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Correct, but conventional flow (the kind they teach in electrical engineering courses) is from positive to negative, which is the direction of the "arrow" in diode and transstor diagrams. Also, to be even more pedantic, "hole" flow is the flow of positive charge carriers, and so is the flow of positive ions in water.
FILETIME to time_t
| FoldWithUs! | sighist | WhoIncludes - Analyzing C++ include file hierarchy -
FET transistors can replace relays in a dc circuit by properly biasing them. I haven't kept up with current parts, but even 20 years ago they were handling 100A loads. I'm sure they can do better today. The nice thing about FETs is that the gate terminal draws near zero current, so it's easy to set switching thresholds using a simple resistor divider. I can't look too closely at the circuit right now, as my employer actually expects me to work on job related stuff while I'm here, but I'll take another look tonight.
Will Rogers never met me.
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FILETIME to time_t
| FoldWithUs! | sighist | WhoIncludes - Analyzing C++ include file hierarchy -
For those who are electronically inclined: http://www3.telus.net/pja/circuit.png[^] I was wondering if there was a way to replace the three internal relays with something else in order to make the circuit solid state. I know that a normally open relay can be replaced with a transistor, but what about a normally closed one? Is there a component that will break a circuit when power is applied to it? Similar to a transistor but with the opposite effect. Also, do I have my diodes in the correct direction? Does DC power flow from positive to negative or the othe other way around? Thanks
You may be right I may be crazy -- Billy Joel -- Within you lies the power for good - Use it!
NOT ELECTRONICS ENOUGH!!!
"Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside in a cloud of smoke, thoroughly used up, totally worn out, and loudly proclaiming "Wow! What a Ride!" — Hunter S. Thompson
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FET transistors can replace relays in a dc circuit by properly biasing them. I haven't kept up with current parts, but even 20 years ago they were handling 100A loads. I'm sure they can do better today. The nice thing about FETs is that the gate terminal draws near zero current, so it's easy to set switching thresholds using a simple resistor divider. I can't look too closely at the circuit right now, as my employer actually expects me to work on job related stuff while I'm here, but I'll take another look tonight.
Will Rogers never met me.
Roger Wright wrote:
my employer actually expects me to work on job related stuff while I'm here
Sounds unreasonable to me.
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Correct, but conventional flow (the kind they teach in electrical engineering courses) is from positive to negative, which is the direction of the "arrow" in diode and transstor diagrams. Also, to be even more pedantic, "hole" flow is the flow of positive charge carriers, and so is the flow of positive ions in water.
Yes, the flow of something non existant is how it rationalised. Great stuff electricity, everyone uses it, no one knows how the hell it works! :)
"If climate has not "tipped" in over 4 billion years it's not going to tip now due to mankind." Richard S. Lindzen, Atmospheric Physicist, IPCC "It does not matter who you are, or how smart you are, or what title you have, or how many of you here are, and certainly not how many papers your side has published, if your prediction is wrong then your hypothesis is wrong. Period." Professor Richard Feynman
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Yes, the flow of something non existant is how it rationalised. Great stuff electricity, everyone uses it, no one knows how the hell it works! :)
"If climate has not "tipped" in over 4 billion years it's not going to tip now due to mankind." Richard S. Lindzen, Atmospheric Physicist, IPCC "It does not matter who you are, or how smart you are, or what title you have, or how many of you here are, and certainly not how many papers your side has published, if your prediction is wrong then your hypothesis is wrong. Period." Professor Richard Feynman
It makes more sense if you think of holes as being analogous to bubbles. :)
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FET transistors can replace relays in a dc circuit by properly biasing them. I haven't kept up with current parts, but even 20 years ago they were handling 100A loads. I'm sure they can do better today. The nice thing about FETs is that the gate terminal draws near zero current, so it's easy to set switching thresholds using a simple resistor divider. I can't look too closely at the circuit right now, as my employer actually expects me to work on job related stuff while I'm here, but I'll take another look tonight.
Will Rogers never met me.
I defer to you, o great one, but would you recommend an SCR for high loads instead? Or are those only for AC? /ravi
My new year resolution: 2048 x 1536 Home | Articles | My .NET bits | Freeware ravib(at)ravib(dot)com
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It makes more sense if you think of holes as being analogous to bubbles. :)
Its amazing what the brain can come up with to convince itself something impossibly illogical is real. :)
"If climate has not "tipped" in over 4 billion years it's not going to tip now due to mankind." Richard S. Lindzen, Atmospheric Physicist, IPCC "It does not matter who you are, or how smart you are, or what title you have, or how many of you here are, and certainly not how many papers your side has published, if your prediction is wrong then your hypothesis is wrong. Period." Professor Richard Feynman
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Its amazing what the brain can come up with to convince itself something impossibly illogical is real. :)
"If climate has not "tipped" in over 4 billion years it's not going to tip now due to mankind." Richard S. Lindzen, Atmospheric Physicist, IPCC "It does not matter who you are, or how smart you are, or what title you have, or how many of you here are, and certainly not how many papers your side has published, if your prediction is wrong then your hypothesis is wrong. Period." Professor Richard Feynman
I thought you weren't going to mention that stuff around here. ;P
Chris Meech I am Canadian. [heard in a local bar] In theory there is no difference between theory and practice. In practice there is. [Yogi Berra] posting about Crystal Reports here is like discussing gay marriage on a catholic church’s website.[Nishant Sivakumar]
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For those who are electronically inclined: http://www3.telus.net/pja/circuit.png[^] I was wondering if there was a way to replace the three internal relays with something else in order to make the circuit solid state. I know that a normally open relay can be replaced with a transistor, but what about a normally closed one? Is there a component that will break a circuit when power is applied to it? Similar to a transistor but with the opposite effect. Also, do I have my diodes in the correct direction? Does DC power flow from positive to negative or the othe other way around? Thanks
You may be right I may be crazy -- Billy Joel -- Within you lies the power for good - Use it!
-
NOT ELECTRONICS ENOUGH!!!
"Life should not be a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside in a cloud of smoke, thoroughly used up, totally worn out, and loudly proclaiming "Wow! What a Ride!" — Hunter S. Thompson
