zener diode in series - Page 1
Forum section: electronics / beginners

author: ascot
author_rank: Contributor
timestamp: January 27, 2021, 09:12:01 am
content: if i connect 2 1 watt zeners in series will they share the watts of a 2 watt circuit

author: gnuarm
author_rank: Super Contributor
timestamp: January 27, 2021, 09:15:34 am
content: P = E * ISo what will the voltage and current be on each zener diode?

author: ascot
author_rank: Contributor
timestamp: January 27, 2021, 09:19:34 am
content: the voltage is 30 current 60 watts 2.00 watts only got 1 watt resistors thinking being would the 2 in series share the watts

author: ascot
author_rank: Contributor
timestamp: January 27, 2021, 09:51:55 am
content: answered my own question they do operating around 50 Celsius

author: gnuarm
author_rank: Super Contributor
timestamp: January 27, 2021, 11:09:27 am
content: Quote from: ascot on January 27, 2021, 09:19:34 amI can't make sense of this. "voltage is 30 current 60 watts 2.00 watts" What???

author: ascot
author_rank: Contributor
timestamp: January 27, 2021, 12:03:04 pm
content: if you have 2 zeners in series ie 2 6.5 volt zeners that would give you 13 volts if each of them is 1 watt and you have a circuit with 30 volts producing 2 watts of power then the original question would be can they share the 2 watts to reduce the heat on them which through testing seems they do running at about 50 celcius

author: gnuarm
author_rank: Super Contributor
timestamp: January 27, 2021, 12:32:33 pm
content: Quote from: ascot on January 27, 2021, 12:03:04 pmThe circuit is not at all clear. What is the circuit dissipating 2 watts of power? If you have two 6.5V zener diodes and you connect them in series to a 30V power supply the resulting current will be very high indeed. No?So I have no idea what you think the circuit is or what the circuit really is. Rather than talking about "sharing" power, focus on what you know about electricity and calculate the power in each part by multiplying the voltage on each device and the current through it.

author: ascot
author_rank: Contributor
timestamp: January 27, 2021, 02:03:03 pm
content: the resulting current was somewhere in the region of 65 mA thats after i added resistor 260 ohm which would have given me roughly 2 watts 65mA x 30 voltsyou have 2 ,1 watt 6.5 volt zener diodes in series given you a combined 13 volts thus each sharing the heat from the 2 watts not overheatingi tested it it works diodes don't overheat

author: gnuarm
author_rank: Super Contributor
timestamp: January 27, 2021, 07:17:15 pm
content: Quote from: ascot on January 27, 2021, 02:03:03 pmI don't see where you learned anything. If you calculate the power in the two zener diodes you might learn something. Can you do that?

author: ascot
author_rank: Contributor
timestamp: January 27, 2021, 10:26:01 pm
content: if you go back to the original question vague as it was.can 2 zener in series share the power dissipation the answer would be yesthe answer comes first then later on the maths,physics,algebra if i had done the maths first i wouldn't be in a forum titled beginners

author: gnuarm
author_rank: Super Contributor
timestamp: January 28, 2021, 02:06:00 am
content: If you don't want to learn any math, you will always be a beginner and understand nearly nothing in electronics. It's pretty much all math. What you did on this was not unlike someone teaching you to drive by handing you the keys and saying, "good luck".

author: TheNewLab
author_rank: Frequent Contributor
timestamp: January 28, 2021, 05:30:48 am
content: Look It's a Troll! see the photo? LOL!I hate math, well, not really, but I hate what electrical engineering expects. I much prefer to do and learn by trial and error..Uh, without being dangerous. Today, their are so many books, online calculators, some wonderful "electronics" phone apps, etc, etc.That was a fair question. I, we, are glad you asked it, and are delighted you solved it, in whichever manner!What was an odd, old phrase I heard? Ah yes "Keep on Trucking ON!"Cheers!

author: gnuarm
author_rank: Super Contributor
timestamp: January 28, 2021, 08:21:28 am
content: P = E * IYup, that's pretty hard. If you can't handle that, you will be forever limited in what you can do in electronics. More importantly, by using math you might actually learn something useful about your circuit. Your verbal analysis of the power dissipation is not right, but it requires using the above formula to figure that out.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 28, 2021, 11:56:50 am
content: Resistors in parallel will share power so if you needed say 180R 2w you can put two 1w 360R in parallel. Zeners in series will approximately share given the tolerance is usually 5% put then in close proximity- zener voltages wanders with temperature.TipAlways include a drawing of your circuit and what you want it to do.You'll bet better answers and fewer bitchy remarks from people who ought to know better.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 28, 2021, 03:34:39 pm
content: See attached.there is no more to be said.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 30, 2021, 09:37:35 pm
content: Quote from: gnuarm on January 28, 2021, 08:21:28 amIn which country is the voltage denoted by E and not U?

author: TimFox
author_rank: Super Contributor
timestamp: January 30, 2021, 09:56:35 pm
content: It’s the old term “emf”. In the US, potential or voltage is now usually denoted asVin italic, while the unit volt is denoted by V in Roman type. I sawElike this often in my long-past youth, and it is still common to see minisculeeto denote noise voltage density, etc.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: January 30, 2021, 10:17:48 pm
content: Quote from: TimFox on January 30, 2021, 09:56:35 pmI wonder how American physicists feel about this, or do they also writeV?V=24V...By the way, I saw it once in one of the forums P=V*A.And the EMF, it seems, denote Ԑ (Greek epsilon).

author: TimFox
author_rank: Super Contributor
timestamp: January 30, 2021, 10:32:30 pm
content: I am a physicist by training. Looking at two (older) physics textbooks from my undergraduate education, both of them useVto indicate (scalar) electric potential (or potential difference).D Halliday and R ResnickPhysics, parts I and II, John Wiley & Sons 1966 (pp 708 ff) and D R Corson and P LorrainElectromagnetic Fields and Waves, W H Freeman 1962 (pp 438 ff for radiation, chap 2 for electrostatics).The "curly E" (or majuscule Greek epsilon) is often used for "electromotive force" (more properly "electromotance", since it is not a force), the integral of the electrostatic fieldEaround a loop induced by changing magnetic flux (Faraday induction law), which is also measured in V (volts).We used to say that a "real physicist" would always put italic minuscule "v" for velocity and minuscule Greek nu for frequency in the same equation to confuse the uninitiated.Your example of "P = V*A" is an example of why we should be careful to italicize variables and romanize units so as not to confuse area and amperes. Why did he need the complex conjugate ofV?

author: gnuarm
author_rank: Super Contributor
timestamp: February 01, 2021, 09:01:18 am
content: I'm not sure why anyone would take issue with using E for voltage, but a google search foundV = I x R 6.5 mil hitsE = I x R 6.3 mil hitsU = I x R 4.5 mil hitsSo clearly U is not remotely universal.

author: S. Petrukhin
author_rank: Super Contributor
timestamp: February 01, 2021, 11:05:46 am
content: Quote from: gnuarm on February 01, 2021, 09:01:18 amYou are misinterpreting the results. The least number of requests from the search engine indicates that "U" know and ask much less.

author: Zero999
author_rank: Super Contributor
timestamp: February 01, 2021, 12:26:19 pm
content: Who cares whetherV, V, U, or E is used? The context will make it obvious, what's what. It should also be obvious whether one is refering to area, or current, by the wording.Quote from: ascot on January 27, 2021, 02:03:03 pmA schematic would help. Presumably you have two zener diodes, connected to a 30V power supply, via a 260R resistor? If so, those figures make perfect sense. The power taken from the 30V power supply is just under 2W. Now calculate the power dissipated by R1, D1 and D2. Hint: they should add up to 1.95W.Note to others: please allow the original poster to attempt this themselves, before providing the solution!

author: TimFox
author_rank: Super Contributor
timestamp: February 01, 2021, 02:59:12 pm
content: Quote from: gnuarm on February 01, 2021, 09:01:18 am\A quick look through my technical library shows older engineering texts usingE, European books usingU, and American physics texts usingV. However, I maintain that careful writers should italicize variables and romanize units, whichever letter they choose.SeeA Manual of Style, 12th ed, Univ of Chicago Press, 1969, chapter 13 for why publishers refer to equations, etc. as "penalty copy".