Chapter 21

Series Resistance

current is the same

Eeq and Req are sums

Parallel Resistance

Voltage is the same

Ieq= sums

1/req= 1/r + 1/r …

For current out of the positive terminal delta VPS=

= E − Irint

For current into the positive terminal:

E + Irint

Junction rule (current rule)

sum of all current enteringa junction must equal the sum of all current leaving

Junction Rule (AKA Current Rule)

Loop Rule (AKA Voltage Rule)

sum of all of the potential difference across all elements around a closed circuit loop =0

Voltmeters have

a very large resistance and are connected in parallel.

Ammeters have a

very small resistance and are connected in series.

in rc circuits a time constant is

t =RC

changing circuit eqs

When capacitors are fully charged,

the current is zero (like an open switch).

When capacitors have zero charge,

ΔVC is zero (like a short circuit).