physics d.c circuits

circuit diagrams

series circuit

only has one path for current (thus current remains constant for every component) I=I1=I2
as current passes through all the resistors, theres a drop in electrical potential resulting in p.d across each component (component with highest resistance will have highest p.d)
V=V1+V2
proportionality applies to p.d

parallel circuit

more than one path for current to flow (I=I1+I2)
p.d for each path is the same as it is connected in parallel to the battery (V=V1=V2)
proportionality applies to current

bypass/ short circuit

bypass is an alternative path of zero resistance for current to flow
short circuit is an unintentional bypass (causes fire etc)

potential divider

voltage divider that makes use of voltage drop across resistors in series to divide voltage
can consist of
- two fixed resistors in series
- a variable resistor and a fixed resistor
- a light-dependent resistor (LDR) and a fixed resistor
- a potentiometer

variable resistors

light-dependent resistor(LDR)
thermistor
potentiometer

current divider

parallel circuit in which the currents divide inversely proportional to the parallel branch resistances.