l8 clipper clamper
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8/9/2019 L8 Clipper Clamper
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• Rectifcation – transorming AC signalinto a signal with one polarity
– Hal wave rectifer
Recall Lecture 6
• Full Wave Rectifer – Center tapped
– ridge
• Rectifer parameters
– !uty Cycles
– "ea# $nverse %oltage &"$%'
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Clipper and ClamperClipper and Clamper
CircuitsCircuits
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Clippers● Clipper circuits, also called limiter circuits, are used to eliminate
portion of a signal that are above or below a specified level – clip value.
● The purpose of the diode is that when it is turn on, it provides the clip
value
● Clip value = V’. To find V’, use KV at !
● The e"uation is # V’ – V$ % Vγ = & V’ = V$ ' Vγ
Then, set the conditions
(f Vi > V’, what happens) diode conducts, hence Vo = V’
(f Vi < V’, what happens) diode off, open circuit, no current flow, Vo = Vi
L1
Vi
%( ) % * %
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For the circuit shown +elow s#etch the waveorm o theoutput voltage, %out- .he input voltage is a sine wave
where %in ) /0 sin ωt- Assume %γ ) 0-1 %
23A4"L2
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Parallel Based Clippers
*ositive and negative clipping can be performed simultaneousl+
b+ using a double limiter or a parallel-based clipper .
The parallel%based clipper is designed with two diodes and two
voltage sources oriented in opposite directions.
This circuit is to allow clipping to occur during both c+clesnegative and positive
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Clipper – !iode in 5eries
"ro+lem -//Figure "-//&a' shows the input voltage o the circuit as shownin Figure "-//&+'- "lot the output voltage %o o these circuits i
%γ ) 0-1 %
P3.11(a) P3.11(b)
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Clampers● Clamping shifts the entire signal voltage
b+ a -C level.
Consider, the sinusoidal input voltage
signal, v I .
!st &&, the capacitor is charged up to
the pea/ value of Vi which is VM.
Then, as Vi moves towards the –ve
c+cle,
the diode is reverse biased.
(deall+, capacitor cannot discharge,
hence Vc = V0
$+ KV, we get
NOTE# The input signal is shifted b+ a dc
level and that the pea/%to%pea/ value is
the same
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Clampers
STEP 1# Knowing what value that the capacitor is charged to. Ad !r"m
the p"larit# "! the di"de, we /now that it is charged during positive
c+cle. 1sing KV,
V$ % V& ' VS ( ) V$ ( VM ' V&
STEP *# 2hen the diode is reversed biased and VC is alread+ a constant
value
VO ' VS % V$ ( ) VO ( VS ' V$.
●
3 clamping circuit that includes an independent voltage sourceV
B.Pea+ ,alue VM
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23A4"L2 – clampers with idealdiodeFor the circuit shown in fgure +elow, s#etchthe waveorms o the output voltage, %out-
.he input voltage is a sine wave where %in )
70 sin ωt- Assume ideal diodes-
%in