# Datasheet Question

Discussion in 'General Electronics Chat' started by waldopulanco, Nov 27, 2013.

1. ### waldopulanco Thread Starter New Member

Nov 14, 2013
26
0
i was wondering on how to read a datasheet for transistor i mean i mean if i want to bias or operate the transistor how to prevent it from damaging,
i have read the data sheet and i want to know some basic info example

Code ( (Unknown Language)):
1. collector-base voltage = 55V condition open emitter
2.
3.
4.  Collector-emitter voltage = 55V condition RBE = 10 Ohms
5.
6.
7.  Collector-emitter voltage = 30V condition Open Base
8.
9.
10.  Emitter-base voltage = 3.5V condition open collector
11.
12.
13.  Collector current(DC) = 0.4A
14.
15.
16.  collector current peak value = 0.4A
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18.
19.  total power dissipation = 3.5W condition up to Tmb = 25 °C
20.
21.
22.  storage temperature = +200 °C
23.
24.
25.  junction temperature = 200 °C
26.
27.
28.  Power Output  = 1W

Please can you explain it!! i want to know some basic information in datasheet!!

Apr 30, 2011
1,568
442
If you'd post a link to the actual datasheet you'd get more useful responses.

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Nov 14, 2013
26
0
4. ### crutschow Expert

Mar 14, 2008
21,416
6,137
I would think you understand some of those data sheet values. For example it would seem apparent that you shouldn't ever exceed the voltage, power or current ratings when using the device in a circuit. Which ones do you find particularly confusing?

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5. ### waldopulanco Thread Starter New Member

Nov 14, 2013
26
0

As an example the total power dissipation is 7 watts, what wattage can only apply during operation to avoid destroying the transistor? half of the total power dissipation or 3.5watts or 2watts?

thanks!!

6. ### MrChips Moderator

Oct 2, 2009
18,207
5,722
You would want to use a heat sink on that transistor.

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7. ### Alec_t AAC Fanatic!

Sep 17, 2013
9,453
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You should always design a circuit such that the transistor operates well within its ratings. The bigger the margin you allow, the longer the life of the transistor is likely to be. With few exceptions I would aim to keep voltage/current/power at no more than 70% or so of the maximum.

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8. ### crutschow Expert

Mar 14, 2008
21,416
6,137
For that amount of power you need a heat sink for the transistor as MrChips stated. You need to look at the thermal resistance of the transistor junction-to-case (θjc given in °C/W) and then determine the thermal resistance of the heat sink you need to dissipate the power at the highest ambient temperature the device will see while keeping the device junction temperature below its maximum rating by at least 25°C.

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