Practically, diodes can
be used as a switch depending on the biasing type, reverse or forward. The
clamping circuit or clamper keeps the amplitude of the output signal same as
that of the input signal except that the D.C level (offset) has been changed
What is a clamper circuit?
A clamper, simply
defined, is a network, which constructed using a diode and a capacitor, shifts
the waveform to a different dc level without changing the appearance of the
applied signal 2. It is the circuit that places either positive or negative
peak of input signal at the desired level. From this definition, we should note
It consists of diode, resistor and
It shifts an ac signal into a different
dc level-that is, applying a sinusoidal waveform at the input produces another
sinusoidal waveform at the output;
It does not change wave shape and
Further shift in the dc level is
possible by adding external bias voltage.
it is of incredible
significance that we take into thought that a clamper can be described as an
electronic circuit which anticipates any input signal from surpassing a certain
characterized size by moving its comparing Dc value. A diode is one of the
vital components in a diode clamp circuit. The diode conducts electric current
in as it were one course. The resistors and capacitors in the circuit are
utilized to preserve a changed DC level the clamper output. These circuits
essentially clamp a crest of a waveform to a particular DC level compared with
a capacitive coupled signal which swings around its normal DC level (as a rule
0V). In the event that the diode is evacuated from the clamper, it defaults to
a straightforward coupling capacitor – no clamping.
The clamper, for all intents and purposes, does not limit the
peak-to-peak outing of the signal, but moves it up or down by a settled value.
The distinctive sorts of clampers are positive negative and one-sided clampers.
A positive clamp circuit yields a simply positive waveform from an input
signal; it offsets the input signal so that all of the waveform is more
noteworthy than 0V. a negative clamp is the inverse of this – this clamp yields a simply negative waveform
from an input signal. A clamping arrangement must have a capacitor, a diode and
a resistive component. The size R and C must be chosen such that the time
steady RC is expansive sufficient to guarantee that the voltage over the capacitor
does not release essentially amid the interim the diode is non-conducting.
The positive or negative
top of a signal can be situated at the cravel level by utilizing the clamping
circuits. As we can move the levels of crests of the signal by utilizing a
clamper, subsequently, it is hence called level shifter. The clamper circuit
comprises a capacitor and diode associated in parallel over the load. The
clamper must be chosen such that, amid the conduction of the diode, the
capacitor must be adequate to charge rapidly and amid the non-conducting period
of diode, the capacitor ought to not release radically. The clampers are
classified as positive and negative clampers based on the clamping strategy.
Clampers can be broadly classified into two
types. They are positive clampers and negative clampers.
Positive Clamper: This type of clamping circuit shifts the
input waveform in a positive direction; as a result the waveform lies above a
DC reference voltage. The circuit of the positive clamper is comparative to the
negative clamper but the direction of the diode is altered in such a way that
the cathode of the diode is connected to the capacitor. Amid the positive half
wave cycle, yield or output voltage of the circuit will be the sum of connected
input voltage and the charge stored at capacitor. Amid the negative half wave
cycle, the diode begins to conduct and charges the capacitor exceptionally
rapidly to its greatest value. The output waveform of the positive clamper
shifts towards the positive direction over the 0 volts.
It is nearly comparative to the negative clamper circuit, but
the diode is associated in the inverse direction. Amid the positive half cycle,
the voltage over the yield or output terminals gets to be equal to the sum of
the input voltage and capacitor voltage (considering the capacitor as at first
completely charged). Amid the negative half cycle of the input, the diode
begins conducting and charges the capacitor quickly to its crest input value.
Hence the waveforms are clamped towards the positive direction as appeared