Why cant I just use V=IR for the output voltage in this circuit? Is it because it wants the output voltage, not the voltage through the resistor? Is it that simple?
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Why cant I just use V=IR for the output voltage in this circuit? watch
- Thread Starter
- 26-01-2017 23:05
- 26-01-2017 23:07
Its a voltage divider network.
- 27-01-2017 01:20
Same thing as on the other thread
(Original post by Joinedup)
you'll do I=V/(Rfixed+RLDR) each time (resistances are added because they're in series)
VLDR=I x RLDR
then on to the next value of LDR resistance and calculate the current again.
so in this case
I=Vin / (R1+(R2) [eq1]
Vout=I R2 [eq2]
substitute eq1 for the I in eq2
Vout=(R2 Vin ) / (R1+(R2)
which is the same as what's shown in the book
Vout=Vin x R2/(R1+R2)
and all the rules are obeyed...
same current in both series resistors
sum of voltages across each individual series resistor adds up to the input voltage
voltage across each individual resistor equals the current through that resistor multiplied by it's resistance