Clipper circuits
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Clipper circuits are used to remove parts of a signal that are above or below a defined reference level. There are several types of clipper circuits: unbiased positive and negative clippers which clip either the positive or negative portions of a signal, and biased positive and negative clippers which use an external bias voltage to adjust the clipping level. Unbiased clippers cut off either the positive or negative half of the input waveform based on the diode configuration. Biased clippers allow changing the clipping level by adjusting the bias voltage applied in series with the input signal and diode.
Clipper circuits
- 1. Clipper Circuits LET’S REMOVE UNWANTED PART OF SIGNALS 1 Electronic Devices and Circuits (2131006)
- 2. Index 1. What are clipper circuits? 2. Types of clipper circuits. 3. Unbiased positive clipper. 4. Unbiased negative clipper. 5. Biased series positive clipper. 6. Biased series negative clipper. 2
- 3. What are clipper circuits? Clippers Circuits are used to remove the part of a signal that is above or below some defined reference level. One of the simple example of a clipper is the half-wave rectifier – that circuit basically cut off everything at the reference level of zero and let only the positive-going (or negative-going) portion of the input waveform through. Clipping circuits (also known as limiters, amplitude selectors, or slicers) 3
- 4. Types of Clippers Circuits Unbiased Clipper Circuit Unbiased Positive clipper Unbiased Negative clipper Biased clipper circuit Biased positive clipper Biased negative clipper Clipper circuits 4
- 5. Note: In all the explanations we have considered the diode to be ideal. 5
- 6. Unbiased positive Clippers Positive clippers are used to clip positive portions of the input signal and allow the negative portions of the signal to pass through Figure below shows the input and output signal along with the positive clipper. The positive cycle is completely clipped off by the clipper. 6
- 7. Continued… Section (b) shows the same clipper configuration as it is shown in (a), but the diode is replaced with its equivalent circuit model. When the input signal goes positive, the cathode terminal of diode attains a higher potential than anode. This makes the diode reverse biased. The diode in reverse biased configuration can be modelled as an open switch. This is indicated in the figure. As the diode acts as an open switch, no current flows through the load and hence no output appears across the load. This is the reason why the positive cycle is completely clipped off. 7
- 8. Unbiased Negative clippers Negative clippers are used to clip Negative portions of the input signal and allow the positive portions of the signal to pass through Figure shows the input and output signal along with the negative clipper. The negative cycle is completely clipped off by the clipper. 8
- 9. Continued… Section (b) shows the same clipper configuration as it is shown in (a), but the diode is replaced with its equivalent circuit model. When the input signal goes positive, the anode terminal of diode attains a higher potential than cathode. This makes the diode forward biased. The diode in reverse biased configuration can be modelled as an open switch. This is indicated in the figure. As the diode acts as an closed switch, no current flows through the load and hence no output appears across the load. This is the reason why the negative cycle is completely clipped off. 9
- 10. Biased series positive clipper As shown earlier, we saw that the clipping of the signal takes place as soon as the input signal goes positive. If we want to change/adjust the clipping level of AC voltage, then external biasing voltage must be used. The figure given below shows a biased (series) clipper. 10
- 11. Working 11
- 12. Biased Series negative Clipper As shown earlier, we saw that the clipping of the signal takes place as soon as the input signal goes negative. If we want to change/adjust the clipping level of AC voltage, then external biasing voltage must be used. The figure given below shows a biased (series) clipper. 12
- 13. Working 13
- 14. Thank You 14