Comments on: About Resistor In Circuit Board

By: James

James — Mon, 15 Jun 2015 03:25:42 +0000

I think the main reason for raising the resistor to a height above the PCB is for better heat dissipation (through the exposed leads). This tactic is seen in a lot of rectifiers on the power supply boards too.
I have read some (e.g., 5A, 10A) rectifier datasheets saying that some of their current ratings are based on having a minimum of 10mm lead length on both sides of the body.

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By: Jestine Yong

Jestine Yong — Sun, 30 Sep 2012 23:03:50 +0000

In reply to Bernie Scott.

Hi Bernie,

Thanks for the sharing!

Jestine

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By: Bernie Scott

Bernie Scott — Sun, 30 Sep 2012 22:55:40 +0000

I believe the reason is to help dissapate the heat that the resistor generates. When it is mounted directly touching the board it tends to overheat that area and can also encourage the development of bad solder joints. I have seen 5 watt resistors mounted directly on the board and the board will be badly overheated in that immediate area. The lower the wattage the longer this will take to occur but it will occur...eventually....

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By: admin

admin — Sun, 27 Feb 2011 20:18:58 +0000

HI Amir,

Good explanation and the blog readers will appreciate it.

Jestine

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By: Amir Mukhtar

Amir Mukhtar — Sun, 27 Feb 2011 10:15:09 +0000

Sir Jestine, the above theory is perfect answer. In spite the fact that, The question which you have given above is very thinkable question. But the question also need to be justified why we use resistors in Circuit board. why wont we use other compatible component.
Actually, Resistor is a device which provide resist facility and protection against over current and voltage. OR Resistors are electrical component that resist the flow of charge in circuits.

Also, Resistors having a lot of applications in circuit board and installations procedures different to each other with respect to functions and located environment.

for example, Especially a person who fights against terrorism enemies; like wise, An electronic component that transmits current in direct proportion to the voltage across it. we can use resistors as:

1. use as fuse to protection.
2. use as current limitation.
3. use to set time constant function with capacitor.
4. use to voltage dividing
5. use to control feed back .
6. use to limit overloading .
7. use to resist voltages.
8. use in frequency circuit with filters.
9. use in switching by light dependency (LDR).
10. use parallel in power supply as discharge element.
11. use as regulating current with respect to changes (VR).
12. use as infinite resistivity by rheostat.
13. etc.

These above are the common job of resistance. so therefore, there is no hurdle to be fixed justification, resistor as important component of the applications in circuit boards.

thanks you
REgards
Amir mukhtar

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By: admin

admin — Thu, 04 Mar 2010 03:07:00 +0000

Hi Robel,

Thanks for giving that comment. Sorry i do not repair tape recorder thus i do not have any reference for you. As for the value, it can be 47 ohm since sometimes a burnt reistor may have the value intact but the outer layer burnt. Without the covering it should be no problem and if you worry about the covering you can always use a shrink tube to cover it.

Jestine

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By: Robel Amanuel

Robel Amanuel — Tue, 02 Mar 2010 20:30:53 +0000

Thank you first of all.
I am of the comment that the reason why some resistrors are fixed just almost on the board while others are mounted high above the board is due to the difference in the ventilation requirement of the respective resistor.
but i also have a question here waiting ur comments:
i found a resistor(resistor no. 11 of a sharp type tape recorder Model no.WF-1100W(BK) serial no. 30905385). This resistor is located near the jack of the tape recorder's speakers. Though its covering (including the color bands) is burnt to the extent that its resistance value can not be determined depending on its color band, i found 48 ohm when i cheked it with digital multimeter. However, i am not certain whether this value is the original or not. so:
1. can u offer me a means of identifying the original value of this resistor?
2. if u have a tape recorder of the same type may tell me the value?
3. thirdly do u believe this resistor can still perform well though it is with out covering?

thank you in advance
with all the best wishes
roble!!

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By: admin

admin — Wed, 14 Oct 2009 13:03:39 +0000

Hi Rag,

Thanks for the posting but since i have done this conversion before thus i could not give any expertise advice to you-sorry.

Jestine

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By: raghava

raghava — Tue, 13 Oct 2009 13:03:26 +0000

Respected Sir,

I would like to ask a question about the conversion of CRT color monitor 14 inch into TV. by using a portable black and white TV circuit.

The following resource are available with me.
1. I have a working condition of computer CRT monitor. -14 inch
2. Portable black and white TV in working condition - 1 no -14 inch
3. Portable black and white TV in non working condition - 1 no - 14 inch - circuit is working but picture tube is showing one horizontal line at middle of screen.

Finally I would like to connect the Portable black and white TV circuit to computer CRT monitor. I want to use the computer CRT monitor as a dual purpose. i.e., one is TV and Computer monitor.

I hope that my question is clear and looking forward for ur favourable reply.

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By: john

john — Tue, 22 Sep 2009 02:53:48 +0000

Please visit us for more resistor information. We are leader in Power and precision resistors.

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