Name: dc restorer for waveform level shifting
Uploaded: 2024-07-08T13:20:21.000Z
Duration: 1 min 14 s
Channel: JoVE

Un circuit de pince se compose d’un signal d’entrée variant dans le temps, d’un condensateur et d’une diode. La tension de sortie est mesurée aux bornes de la diode.
Pendant le demi-cycle négatif du signal d’entrée à onde carrée, la diode est polarisée vers l’avant, ce qui entraîne une tension nulle aux bornes de la diode.
Mais en même temps, le condensateur se charge à la valeur de crête du signal d’entrée.
Pendant le demi-cycle positif de l’onde carrée, la diode devient polarisée en sens inverse. Ici, la tension d’entrée et le condensateur chargé agissent comme une source de tension combinée.
À cet instant, la tension aux bornes de la diode est le double de celle de la tension d’entrée. Ce circuit agit comme un pinceur positif.
Lorsqu’une charge est connectée à travers la diode, le courant de sortie circule de la charge à travers le condensateur. Cela réduit la tension de sortie de manière exponentielle en fonction de la constante de temps RC. 
Lorsque la tension d’entrée diminue, la tension de sortie suit et charge le condensateur. Lorsque la tension d’entrée augmente à nouveau, le condensateur se décharge et le cycle se répète

circuit de serrage

Un circuit clamper, également connu sous le nom de restaurateur DC, représente une variante spécialisée du circuit redresseur, remarquable par sa méthode consistant à prendre la sortie aux bornes de la diode plutôt que du condensateur. Cette configuration se prête à plusieurs applications distinctives, en particulier dans la gestion des entrées d'onde carrée.
Dans ce circuit, l’orientation de la diode incite le condensateur à se charger jusqu’au niveau du pic le plus négatif du signal d’entrée. En atteignant cet état, la diode cesse de conduire, bloquant ainsi la tension du condensateur à un niveau constant. Ce mécanisme fait que la tension de sortie est la forme d'onde d'entrée d'origine, élevée d'une valeur égale à la tension aux bornes du condensateur (V_C).
La fonction principale du circuit de serrage est d'ajuster la ligne de base de la forme d'onde. Par défaut, cela élève le point le plus bas de la forme d'onde. La modification de la polarité de la diode inverse cet effet, fixant le pic le plus élevé de la forme d'onde à zéro volt. Cette capacité est particulièrement avantageuse dans les applications impliquant la transmission de signaux impulsionnels via des systèmes à couplage capacitif. Étant donné que le couplage capacitif élimine intrinsèquement la composante continue d'un signal, le circuit de serrage joue un rôle essentiel dans le rétablissement de ce niveau CC, facilitant ainsi une modulation précise du rapport cyclique.
L'inclusion d'une résistance de charge aux bornes de la diode introduit une complexité supplémentaire dans le fonctionnement du circuit. Dans de telles configurations, le condensateur se décharge chaque fois que la sortie s'élève au-dessus du niveau du sol, modifiant subtilement la tension de sortie. Le condensateur reconstitue sa charge dans des conditions stables, garantissant ainsi l'efficacité du circuit pour restaurer et maintenir la composante continue souhaitée dans un signal.

Circuit de serrage

Un circuit de pince se compose d’un signal d’entrée variant dans le temps, d’un condensateur et d’une diode. La tension de sortie est mesurée aux bornes de la diode.
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Clamper Circuit

dc restorer for waveform level shifting

A clamper circuit, or DC restorer, shifts a waveform up or down by adding a DC level. It is a special form of rectifier circuit. In this setup, the output is taken across the diode instead of across the capacitor.

The circuit works well with square wave inputs and other pulse signals. The diode direction lets the capacitor charge to the most negative peak of the input signal. After that, the diode stops conducting. The capacitor then holds that voltage at a steady value.

As a result, the output becomes the original input waveform shifted by the capacitor voltage, V C. By default, the circuit raises the lowest part of the waveform. If the diode polarity is reversed, the circuit clamps the highest peak at zero volts instead.

This function is useful when signals pass through capacitive coupling. Capacitive coupling removes the DC component of a signal. The clamper circuit restores that DC level, which helps preserve accurate duty cycle modulation. Adding a load resistor across the diode changes the circuit behavior further. In that case, the capacitor can discharge whenever the output rises above ground level. Even then, the capacitor recharges in steady-state conditions and continues to support the restored DC component.

DC Restorer for Waveform Level Shifting

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clamper circuit

A clamper circuit, or DC restorer, shifts a waveform up or down by adding a DC level. It is a special form of rectifier circuit. In this setup, the output is taken across the diode instead of across the capacitor. The circuit works well with square wave inputs and other pulse signals. The diode direction lets the capacitor charge to the most negative peak of the input signal. After that, the diode stops conducting. The capacitor then holds that voltage at a steady value. As a result, the...

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key terms and concepts

Learn how a clamper circuit, or DC restorer, shifts waveform levels, restores DC after capacitive coupling, and clamps peaks with a diode and capacitor.

DC Restorer for Waveform Level Shifting | JoVE K12

JoVE Core Electrical Engineering offers easy-to-understand animated videos that cover fundamental concepts of electric circuits along with circuit analysis techniques. It incorporates first-order and second-order circuits using operational amplifiers and circuit transformation concepts. The inclusion of practical design examples and real-world applications through scientist-in-action videos adds significant educational value, making complex concepts accessible.

electrical engineering

DC Restorer for Waveform Level Shifting

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