electric circuits Flashcards
characteristics of seriest circuit current
have the same current everywhere
characteristics of series circuit ressitance and p.d
and all the p.d adds up
resistance= r1 + r2
parralel circuits p.d
p.d is the same
parralell circuits current
current adds up
resistors in parralell circuits
R= (r1 x R2)/(R1+R2)
what are th advantages of parralell circuits
- all the components can be switched on and of independently
- if one lamp breaks, others still work fine
- components in parrallel recieve the p.d they where desighned for
the total resistance of a parralel ccircuit is less or more than any resistor in that cicuit
less
the resistance in parallel is alwars less or more than hat in series
less
is the current from cell greater or smaller in parallel
greater
what is the potential divider
it can be 2 resistors in series or a variable resistor with 3 connections. by adjusting the variable resistor which alters the ratio of 2 resistors, we can control the output voltage
used in eg: dimmer switches, sound volume etc
Vout= R1/R1+R2 x Vin
what are transducers
device that changes forms of energy
what is a thermistor
a thermistor, LDR, microphone are all sensors that convert a form of energy into electricity
what is a direct current
it is made by cells by d.c generators- direct current flows in one direction and has constant size when flowing through a resistor of constant value
what is an alternating current?
alternating currents are made by a ac generator. alternating current repeatedly changes both size and direction. most electricity and power transmissions are ac.
formula of frequency
f= 1/T
