# Diode work

Discussion in 'Homework Help' started by beemovie, Dec 29, 2008.

1. ### beemovie Thread Starter Member

Dec 19, 2008
12
0
Hi !!!
first of all best wishes, Today I have encountered a h.w question which I cannot understand.Please help me out through this. If you can please when you answer write the question number so that I han recognise to which one you're refering.I am still a Beginner.10x
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The diode is silicon in the diagram. Using the second approximation method calculate :
2) The diode voltage
3) The diode current
4) The diode power

HELP ME !!!!

thankyou for now

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Apr 5, 2008
19,006
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Hello,

To solve the question you will need the properties of the diode.

What is the voltage across the diode ?
When you know this the voltage across the resistor can be calculated and its current.

Greetings,
Bertus

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3. ### beemovie Thread Starter Member

Dec 19, 2008
12
0
I still cannot understand it well !!

Apr 5, 2008
19,006
3,762
Hello,

You must know the properties of the diode to get an answer.
It is said it is an silicon diode, I think the forward voltage will be around 0.7 Volts.

Now calculate the voltage accross the resistor, then you can calculate the current and the powers.

Greetings,
Bertus

5. ### beemovie Thread Starter Member

Dec 19, 2008
12
0
Hello

First of thanks for your help Bertus....
I will try to solve this out !! I need to someone confirm it please!!!And help me through 4,5 suggest me which calculations I have to use

2)The diode voltage......Considering it is a silicon diode it is 0.7v
3)The diode current.....I=V/R.. I=0.7/1000= 0.0007mA
4)The diode power==??????????

Apr 5, 2008
19,006
3,762
Hello,

That is not completely correct.
There will be about 0.7 Volts across the diode, this has to be subtracted from the 5 Volt you calculated.

Greetings,
Bertus

7. ### beemovie Thread Starter Member

Dec 19, 2008
12
0
I'll try it again please confirm it for me and someone help me through 4 and 5
2)The diode voltage......Considering it is a silicon diode it is 0.7v
3)The diode current.....I=V/R.. I=4.3/1000= 0.0043mA
4)The diode power==??????????

8. ### eblc1388 AAC Fanatic!

Nov 28, 2008
1,543
104
Watch your unit. Volt divided by R gives Ampere, not milliAmpere.

Apr 5, 2008
19,006
3,762
Hello,

You are still giong wrong.
1) The load voltage : Utop - Ubottom - Udiode = 10 - 5 - 0.7 = 4.3 Volts
2) The diode voltage : Considering it is a silicon diode it is 0.7v
3) The diode current : Uload / Rload = 4.3 / 1000 = 4.3 mA
4) Power current : Udiode * Idiode