When a total voltage ES
is applied across series connected resistances R1
and R2, the current IS
which flows through the series circuit is:
IS = ES / RS
= ES / (R1 + R2)
The voltages V1 and
V2 which appear across the respective
resistances R1 and R2
are:
V1 = ISR1
= ESR1 / RS = ESR1
/ (R1 + R2)
V2 = ISR2
= ESR2 / RS = ESR2
/ (R1 + R2)
In general terms, for resistances R1,
R2, R3, ...
connected in series:
IS = ES / RS
= ES / (R1 + R2 + R3
+ ...)
Vn = ISRn
= ESRn / RS = ESRn
/ (R1 + R2 + R3 + ...)
Note that the highest voltage drop
appears across the highest resistance.