Part 3 First-order Filter Circuits Flashcards
What order transfer function does a first-order filter have?
1st order transfer function
What does it mean to have a 1st order TF?
Highest power of s or jw in the num or den is 1
what does attenuate mean
to reduce or weaken
what does a low pass filter do
passes low frequencies and attenuates high frequencies
what does a high pass filter do
passes high frequencies and attenuates low frequencies
what does a hybrid form filter do
a linear sum of low-pass and high-pass responses
what is the corner frequency (aka 3dB frequency)
divides the low and high frequencies
s is equivalent to…
…jw( j omega)
low-pass standard form in terms of time constant
Vo/Vi=k/(1 + sT)
loss-pass standard form in terms of omega
Vo/Vi= k / (1 + j(W/Wo))
loss-pass standard form in terms of freq
Vo/Vi= k / (1 + j(f/fo))
high-pass standard form in terms of time constant
Vo/Vi = (k*sT)/(1 + sT)
high-pass standard form in terms of omega
Vo/Vi = (k * j(W/Wo))/(1 + j(W/Wo))
high-pass standard form in terms of freq
Vo/Vi = k * (1 + j(f/f1))/(1 + j(f/f2))
for low and high pass the time constant is given by
T = 1/Wo = 1/2pifo
what 2 names are hybrid filters known by
‘pole-zero’ and ‘lead-lag circuit’
hybrid standard form in terms of time constant
Vo/Vi= k. (1 + sT1)/(1 + sT2)
hybrid standard form in terms of omega
Vo/Vi = k. (1 + j(W/W1)) / (1 + j(W/W2)
hybrid standard form in terms of freq
Vo/Vi = k. (1 + j(f/f1)) / (1 + j(f/f2))
for hybrid filter, time constant is given by 2 equations…
T = 1/W2 = 1/2pif2
Before find the tranfser function, what arrangement should your circuit be in?
series
when finding the tf, which impedance is of interest
the Zo impedance
what is the impedance of a capacitor, Xc
Xc = 1/sC = 1/jWC
how do you calculate the tf?
Zo / Zo+Zi
