 myself Sunil Kalshatti, Assistant Professor, Department of Electronics Engineering, Vachan Institute of Technology, Solapur. Today, I am going to explain the Clippers from Electronic Circuit, Analysis and Design 1. Learning outcome. At the end of this session, students can analyze wave-shaping circuits. Clipper. A clipper is a type of diode network that has the ability to clip off a portion of input signal without distorting the remaining part of the alternating waveform. It removes signal voltage above or below specified level. The circuit in which the waveform is shaped by removing or clipping a specific portion of the input signal without distorting the remaining part of the alternating waveform is called as a clipper. Clippers are also called as limiters or slicers. What are the images of clipper circuits? Clippers are used to remove portion of signal that contain noise. Clippers are used for wave-shaping. Clippers are used for protection of circuit against high voltage. There are four general categories of clippers. Positive clipper, negative clipper, biased clipper and combination clipper. Positive clipper, negative clipper and biased clippers are again divided in two different types, series and shine. Whereas combination clipper, it is the combination of both positive clipper and negative clipper. So, first type, positive clipper. Series, positive clipper. In this circuit, the positive half-cycle of the input voltage will be removed and the main control element is connected in series. That's why the name is the series positive clipper. The circuit is as shown. So, let us see how it works. So, during positive half-cycle, diode D is forward bias. Sorry. During positive half-cycle, diode D is reverse bias. It acts as an open. Therefore, circuit is incomplete. So, effect of this, the current is zero. Therefore, load voltage is zero. During negative half-cycle, diode D is forward bias. It acts as a closed circuit. Therefore, current flows in the anticlockwise direction. So, effect of this, negative half-cycle is developed across the load. In this circuit, the positive half-cycle is removed from the supply. That's why name is the series positive clipper. Transfer characteristics of series positive clipper. When V in is positive, diode D is reverse bias. It acts as open. Therefore, for complete duration, V zero is the zero. Whereas in the negative half-cycle, as V in changes negatively, diode D is forward bias. Therefore, output follows the input. So, effect of this, transfer characteristics is like this. Shunt positive clipper. In this circuit, the main control element is connected in parallel and it removes the positive half-cycle of the input voltage. That's why name is the shunt positive clipper. So, let us see how it works. During positive half-cycle, diode D is forward bias. It conducts. It acts as a short. In this circuit, the load is connected across the diode. For complete positive half-cycle, diode D is forward bias. So, effect of this, the drop across diode and drop across load is same. So, for complete positive half-cycle, the drop across load is zero. And during negative half-cycle, diode D is reverse bias. It acts as open. Therefore, output follows the input. Means negative half-cycle is appears across the load. In this circuit, the positive half-cycle will be removed from the circuit. That's why name is the shunt positive clipper. Transfer characteristics. During positive half-cycle, V in is positive. But the voltage across load is zero. And during negative half-cycle, as V in changes, according to that, V zero changes. Therefore, transfer characteristics is like this. What happens if position of diode will be reversed of the series positive clipper? Already we have seen. In the series positive clipper, during positive half-cycle, diode D is reverse bias. But if we reverse the position of the diode. So, effect of this during positive half-cycle, diode D becomes forward bias. So, circuit becomes complete. So, during positive half-cycle, positive voltage is developed across the load. And during negative half-cycle, diode D becomes reverse bias, circuit becomes incomplete. So, the load voltage is zero. Means if we reverse the position of the diode in the series positive clipper, the positive half-cycle is appears across the load whereas it clips the negative half-cycle. Negative clipper, series negative clipper. In this circuit, the main control element is connected in series. And it clips the negative half-cycle. That's why name is the series negative clipper. So, let us see how it works. During positive half-cycle, diode D is forward bias. It acts as a closed switch. So, effect of this, the current flows in the clockwise direction. So, voltage is developed across the load. So, for complete positive half-cycle, positive half-cycle is appears across the load. And during negative half-cycle, diode D is reverse bias. It acts as a open. Therefore, the voltage across load is zero. Means it clips the negative half-cycle from the supply. Shunt negative clipper. In this circuit, the main control element is connected in parallel with load. And it clips the negative half-cycle. That's why name is the shunt negative clipper. Let us see how it works. During positive half-cycle, diode D is reverse bias. It acts as a open. Therefore, output follows the input. And during negative half-cycle, diode D becomes forward bias. So, it conducts and current flows in the anti-clockwise direction. Here, the load is connected across the diode. So, for complete negative half-cycle, diode remains in conducting set. So, the drop across load is zero. Means it clips the negative half-cycle. Transfer characteristics. It is same for the series and shunt negative clipper. During positive half-cycle, when wind changes positively, according to that, V0 changes. And during negative half-cycle, when wind changes negatively, but V0 remains zero. We use the ideal diode. Suppose, if we use the practical diode, either silicon or germanium. So, effect of this, for positive clipper, the 0.7 is developed across the load for complete positive half-cycle. And for negative half-cycle, minus 0.7 is developed. And suppose if we use the germanium, then the drop across diode is 0.3. Means 0.3 is appears across positive half-cycle and appears in the negative half-cycle. Biased series positive clipper. In some application, it is required to remove a small portion of positive or negative half-cycle of the signal voltage. Hence, biased clippers are used. The name bias is designated because the adjustment of clipping level is achieved by adding a biasing voltage in series with diode. A clipper circuit in which diode is connected in series to the input signal and biased with positive reference voltage Vr and that attenuates the positive portion of the waveform is termed as the positive series clipper with positive Vr. The above circuit is biased series positive clipper. Here, the battery is connected in series with R. During positive half-cycle, as long as supply is less than Vr, for this duration, diode is forward biased, it conducts, so circuit becomes complete. So, as long as Vn is less than Vr, output follows the input, means output changes according to the input. Once the Vn crosses Vr, diode D becomes reverse biased, it acts as an open, therefore, circuit becomes incomplete. Therefore, when Vn crosses Vr, the output becomes Vr. And further, in the positive half-cycle, whenever the Vn becomes less than Vr, again diode D becomes forward biased, therefore, output follows the input. And in negative half-cycle, for complete negative half-cycle, diode D becomes forward biased and output follows the input. Transfer characteristics of biased series positive clipper. During positive half-cycle, as long as Vn is less than Vr, diode D is forward biased, it acts as a closed circuit, so circuit becomes complete. So, as Vn is changes, V0 is changes for this duration. When Vn crosses reference level, diode D becomes reverse biased, it acts as open, therefore, output is equal to Vr. And again, in the complete negative half-cycle, the Vn is less than Vr, diode D is in conducting set, so circuit becomes complete. So, effect of this output follows the input. These are references. Thank you.