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Electronics => Electronics => Topic started by: ed1380 on December 30, 2007, 02:24:48 PM

Title: schematic questions
Post by: ed1380 on December 30, 2007, 02:24:48 PM

i scavanged though a TV and got me some stuff. now I'm looking through the datasheest to see what it is.

heres teh prob.

in teh attached pic it says
R1//R3
R2//R4


what does // mean? is it the same as / ?



and whats RL?

thanks

Title: Re: schematic questions
Post by: Admin on December 30, 2007, 03:30:15 PM

you forgot to link us to the KA278RA05 datasheet (http://www.ortodoxism.ro/datasheets/fairchild/KA278RA05.pdf) ;D

RL is the load resistance.

For example, an mcu will have some internal resistance, and that will be the load. RL just represents whatever circuitry to attach to the voltage output.

R1//R3
R2//R4

=

R1/R3
R2/R4

basically divide, although I'm not sure why its // instead of / . . .

Title: Re: schematic questions
Post by: ed1380 on December 30, 2007, 03:54:23 PM

i did attach SS of what i was talking about (http://forums.extremeoverclocking.com/images/smilies/good.gif)

thanks.


so can i just ignore RL?

Title: Re: schematic questions
Post by: Darkbluestar on December 30, 2007, 05:44:00 PM

In my EE (elecrical engineering) classes we often use the symbol || to stand for "in parallel with". So it is possible that whoever made this intended to use that notation. In which case (R1//R3)/(R2//R4) stands for the value of R1 in parallel with R3 divided by R2 in parallel with R4.

Title: Re: schematic questions
Post by: ed1380 on December 30, 2007, 06:04:11 PM

what does "in parralel with" mean

how woudl i use it as an equation?

Title: Re: schematic questions
Post by: Darkbluestar on December 30, 2007, 06:27:39 PM

Two resistors in parallel like R1 and R2 can just be plugged into an equation (R1*R2)/(R1+R2).
You can read all about it here, http://en.wikipedia.org/wiki/Resistor#Series_and_parallel_circuits (http://en.wikipedia.org/wiki/Resistor#Series_and_parallel_circuits)

Title: Re: schematic questions
Post by: ed1380 on December 30, 2007, 06:31:18 PM

i think you might have hit the nail on the head. cause inside that IC there are 2 internal resistors.

thanks

Title: Re: schematic questions
Post by: Darkbluestar on December 30, 2007, 06:34:52 PM

you're very welcome