Simple Electronics question

Zetsu

I am following though the NEET modules... and on page 3-46 of the first book It is talking about 'source resistance'. My question is two parts..

1. Do I need to really be concerned with this... Source Resistance.....

2. The schematic shows a Voltage source of 15V and 3 resistors at 2 ohms 4 ohms and .5 ohms.... as well as a variable load resistor

now the description says:
the effect of the source resistance on the power output of a dc source may be shown by an analysis of the curcit in figure 3-36 When the variable load resistor is set at the zero-ohm postion
current is calculated using the following formula:

I guess I could add that its a Series circuit and very simple.....

i = Es/Ri = 100V / 5 Ohms = 20 Ampers....


!!!!!!!!!!!!!!!!!!!!!!!! where did... yeah the 100V and 5 Ohms comes from.... ?

p.s who would win ? Laser army or Mirror army ?

kwinn

Sounds like a typo or misplaced schematic to me. If what you state in sentence #2 is correct the current would be I = Es/Ri = 15V/(2 + 4 + 0.5) = 15/6.5 = 2.30769...A

LoopyByteloose

I took a look at the text. I doubt there is a typo. I think you are looking at the wrong schematic in relationship to the table referred to in figure 3-36.

I suppose "Source Resistance" maybe jargon for the internal resistance in a battery. If you are using a regulated voltage source, I would imagine that it would not apply. But if you want to squeeze the most out of a battery, it is useful.

NEETS is rather old. I like it, but some of the concepts they call attention to are not very useful in modern electronics.

They just want you to be aware that batteries work more efficiently with small loads.

Zetsu

Awesome, thank you