DC Capacitor - Difference Between +ve and -ve Plates - CR4 Discussion Thread

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justinanto1987 Power-User Join Date: Sep 2010 Location: Thrissur, Kerala, India Posts: 177 Good Answers: 3	DC Capacitor - Difference Between +ve and -ve Plates 09/04/2010 5:12 AM
	In DC Capacitor, +ve and -ve plates are specified. But AC capacitor can connect anyway. If we are connecting the DC capacitor by reversing it's terminals, it will not work. My question is what is the difference in the construction of between +ve and -ve plates. When I asked this question to a electronics technician he gave me the reply as there is some fluride coating in +ve plate. If so what is the material is used for coating? Why -ve plate is showing affinity to receive electrons and why not it deliver electrones when voltage is applied? Same question in case of +ve plate also. Why it is only delivering electrones and why not it receives electrones? __________________ If you can't find a way, make one........
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TonyS Guru Join Date: Aug 2010 Location: Resting under the Major Oak Posts: 4347 Good Answers: 181	#1 Re: DC Capacitor 09/04/2010 6:28 AM
	Having read your other posts in the communications section I would suggest. A/ do your own homework B/ try Google As for 3 6/7^th looks on Google for "The Goons + Buebottle" (from communications section post). Some of the older members may remember the Goons. __________________ The reports of my death are greatly exaggerated.
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TonyS Guru Join Date: Aug 2010 Location: Resting under the Major Oak Posts: 4347 Good Answers: 181	#2 In reply to #1 Re: DC Capacitor 09/04/2010 6:38 AM
	(Orchestral intro) Tenor: There's a song that I recall My mother sang to me. Spriggs (off): Oh! (a sigh) Tenor: She sang it as she tucked me in When I was ninety-three. (harp plays a rising chord...) Spriggs: I diddle, I. Who was that bum? Bluebottle + Spriggs: Ying tong ying tong Ying tong ying tong Ying tong iddle I po, Ying tong ying tong Ying tong ying tong (bluebottle drops behind) Ying tong iddle I po Spriggs: Keep lad up. Keep. Bluebottle: Keep up lad up. Both: Ying tong ying tong Ying tong ying tong Ying tong iddle I po Spriggs: lad Both: Ying tong ying tong Ying tong iddle I po (lad) Iddle I po (lad) Ying tong ying tong Ying tong (Spriggs: iddle) (Bluebottle: ying tong) Ying tong iddle I po Ying tong ying tong iddle Bluebottle (spoken): Ying tong iddle I po! (short raspberry, Secombe) Both: Oh! Ying tong ying tong Ying tong ying tong Ying tong iddle I po Ying tong ying tong Ying tong iddle I po Iddle I po! (trumpet bit) Bluebottle: Ying. Ying tongy tongy. Ying tong iddle I po. Ying tong iddle I po. (Secombe under this: What a lovely lovely boy!) (or Secombe under this: What a lovely melody devine!) Ying ying ying tongy tongy. (Milligan: Get out the rifle, sir.) (or Milligan: Get off the record.) Yeeeng. Ying tong ying tong d'gy-n'o. Ying tong d'ga. (Secombe: Get away.) D'g d'g d'ga. Ying tong iddle I po. Seagoon:Hear that crazy rhythm Driving me insane. Strike your partner on the bonce (bonk?). (thump) Eccles: Ooh. I felt no pain. (Seagoon screeches) Seagoon, Bluebottle and Eccles: Ying tong ying tong Ying tong ying tong Ying... (harp chord rises) Soprano: Take me back to Vienna.... (Raspberry section, probably Milligan) Bloodnok: Ohhhhh! Eccles: Oh! (harp chord) Soprano: Take me back to Vienna, where the.... (crash!) Seagoon, Spriggs and Bluebottle (far off): Ying tong ying tong Ying tong ying tong Ying tong iddle I po Ying tong ying tong Ying tong iddle I po (mad dash to foreground) Ying tong ying tong Ying tong ying tong Ying tong iddle I po (Spriggs: where's he going lad?) (BB: I don't know) Ying tong ying tong Ying tong iddle I po Seagoon: LOOK OUT! (cry from Bluebottle) (mad dash to distance) (hastily) Ying tong ying tong Ying tong ying tong Ying tong iddle I po Ying tong ying tong Ying tong iddle I po (dash to foreground) Ying tong... (whine of bomb dropping, explosion) Double speed, but same tempo, Goons: Ying tong ying tong Ying tong ying tong Ying tong iddle I po Ying tong ying tong Ying tong iddle I po Iddle I po. Ying tong ying tong Ying tong ying tong Ying tong iddle I po Ying tong ying tong Ying tong iddle I po Iddle I po. One: Ying! Tongy tongy tongy. Yiddy diddy diddy da daaa. Ying diddy. Ying tong diddle. Yiddada boo. (rhythmic thigh slapping, raspberry) All Ying tong ying tong Ying tong iddle Ying tong iddle I po Ying tong ying tong Ying tong iddle I po Iddle I po. Eccles: Whoooooh! __________________ The reports of my death are greatly exaggerated.
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justinanto1987 Power-User Join Date: Sep 2010 Location: Thrissur, Kerala, India Posts: 177 Good Answers: 3	#3 In reply to #1 Re: DC Capacitor 09/04/2010 6:39 AM
	Dear Tony, I tried in google already, but i didn't get the answer for my question. __________________ If you can't find a way, make one........
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TonyS Guru Join Date: Aug 2010 Location: Resting under the Major Oak Posts: 4347 Good Answers: 181	#4 In reply to #3 Re: DC Capacitor 09/04/2010 6:48 AM
	Have a look for electrolytic capacitors DC capacitors have a lower dielectric strength, as they don't have to cope with changes in polarity. Try a dc capacitor at full voltage on AC and wait for the bang. __________________ The reports of my death are greatly exaggerated.
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#5 Re: DC Capacitor - Difference Between +ve and -ve Plates 09/06/2010 3:45 AM
	If electrolytic capacitors are connected the wrong way round they go BANG! __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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justinanto1987 Power-User Join Date: Sep 2010 Location: Thrissur, Kerala, India Posts: 177 Good Answers: 3	#6 In reply to #5 Re: DC Capacitor - Difference Between +ve and -ve Plates 09/06/2010 4:01 AM
	I got all the reply as it will explode if polarity is reversed... I know that. But i am asking why it is happening. There should be some difference in construction between positive and negative electrode & I need to know that difference. I am expecting correct technical reason. __________________ If you can't find a way, make one........
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justinanto1987 Power-User Join Date: Sep 2010 Location: Thrissur, Kerala, India Posts: 177 Good Answers: 3	#7 In reply to #6 Re: DC Capacitor - Difference Between +ve and -ve Plates 09/09/2010 4:54 AM
	Peterg7lyq gave me the answer in another forum. Construction Aluminum electrolytic capacitors are constructed from two conducting aluminum foils, one of which is coated with an insulating oxide layer, and a paper spacer soaked in electrolyte. The foil insulated by the oxide layer is the anode while the liquid electrolyte and the second foil acts as the cathode. This stack is then rolled up, fitted with pin connectors and placed in a cylindrical aluminum casing. The two most popular geometries are axial leads coming from the center of each circular face of the cylinder, or two radial leads or lugs on one of the circular faces. Both of these are shown in the picture. Polarity In aluminum electrolytic capacitors, the layer of insulating aluminum oxide on the surface of the aluminum plate acts as the dielectric, and it is the thinness of this layer that allows for a relatively high capacitance in a small volume. The aluminum oxide layer can withstand an electric field strength of the order of 10⁹ volts per meter. The combination of high capacitance and high voltage result in high energy density. Most electrolytic capacitors are polarized and require one of the electrodes to be positive relative to the other; they may catastrophically fail if voltage is reversed. This is because a reverse-bias voltage above 1 to 1.5 V^[1]^[2]^[3] will destroy the center layer of dielectric material via electrochemical reduction (see redox reactions). Following the loss of the dielectric material, the capacitor will short circuit, and with sufficient short circuit current, the electrolyte will rapidly heat up and either leak or cause the capacitor to burst. This is because, if the aluminium foil with a layer of aluminium oxide on it is made negative the oxide ion will get reduced and will convert into oxygen gas generating a high pressure and hence may burst open the capacitor.^{[citation needed]} This is same as the electrochemical principle in an electrolyte with 2 electrodes. To minimize the likelihood of a polarized electrolytic being incorrectly inserted into a circuit, polarity is very clearly indicated on the case. Also, the negative terminal lead of a radial electrolytic is shorter than the positive lead and may be otherwise distinguishable. On a printed circuit board it is customary to indicate the correct orientation by using a square through-hole pad for the positive lead and a round pad for the negative. __________________ If you can't find a way, make one........
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Anonymous Poster	#8 In reply to #6 Re: DC Capacitor - Difference Between +ve and -ve Plates 09/12/2010 10:43 AM
	Electrolytic capacitor is used in our 11KV side of plant and recently replaced a C with a new one of 117KVAR connecting reverse.But its AC. no bang
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Users who posted comments:

Anonymous Poster (1); justinanto1987 (3); PWSlack (1); TonyS (3)

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