Question bank — Diode clipping and clamping circuits

False. A clamper adds the same constant to every instant, so the vertical gap between the highest and lowest points is untouched — only the offset changes.

True. Clipping only ever holds the output at a flat level once a threshold is crossed; it removes excursion, so peak-to-peak can only stay equal or shrink, never grow.

True for the ideal model, but only there. A real silicon diode needs $V_{\gamma }\approx 0.7\text{ V}$ to conduct, so the peak actually clamps to $\pm 0.7\text{ V}$ (or $V_B+V_{\gamma }$ with a bias battery).

False. A series clipper passes one whole polarity and sends the other to ~$0$; a parallel clipper passes the input until it hits a level, then holds flat there. They clip different things.

True. The battery just moves the threshold to $V_B+V_{\gamma }$; the mechanism (diode conducts past threshold, holds the node) is identical.

True. If $RC$ is small the stored "battery" voltage droops each cycle, so the offset wobbles and the clamp fails. Rule of thumb $RC\ge 10T$; see RC time constant.

False. Reversing the diode turns a negative clamper into a positive clamper (shifts up instead of down). It is still a clamper — the series capacitor is what makes it one.

False. Below threshold the diode is OFF, so no current flows and $v_o=v_i$ unchanged. The $0.7\text{ V}$ only appears inside the clipped (flat) region.

False. The diode stops conducting $0.7\text{ V}$ early, so the capacitor charges only to $V_m-V_{\gamma }$, and the clamped peak lands at $\mp V_{\gamma }$, not exactly $0$ or $\pm V_m$.

True. Everything else is arrangement — where the resistor, capacitor, and battery sit. The diode itself only does the one trick from PN Junction Diode.

Error. A positive clipper's diode conducts on positive peaks, so it holds the top flat at $V_B+V_{\gamma }$; the negative half passes through untouched. "Positive" names the peak that gets sliced.

Error. The whole point of a clamper is to add a DC level (it's a DC restorer). The capacitor charges to a fixed voltage and behaves like a battery — that battery is the added DC. Contrast plain AC coupling and DC restoration which removes DC.

Error. One diode clips only one side. To get an almost-square wave you need two diodes (double-ended clipper), each holding one limit, so both top and bottom are flattened.

Error. That is the negative clamper (positive peak pulled to $0$). A positive clamper puts the negative peak at $0$ and pushes the positive peak up to $+2V_m$. Which peak lands at zero depends on diode orientation.

Error. Track the polarity: the cap charges with $+$ on the input side to magnitude $V_m$, and $v_o=v_i-v_C=v_i-V_m$. Subtracting $V_m$ moves the wave down, so the positive peak drops to $0$.

Error. In a rectifier large $RC$ smooths ripple; in a clamper large $RC$ keeps the stored offset from drooping. Same inequality, different job — here it protects the DC shift, not the smoothness.

So that when the diode conducts and pins the node to a fixed level, the excess input voltage has somewhere to drop (across $R$). Without $R$ the source would fight the clamped node directly.

The diode lets the cap charge quickly on the first peak but blocks fast discharge, and $RC\gg T$ stops slow leakage — so it holds a nearly constant voltage, exactly what a battery in series does.

The diode only conducts once the voltage across it reaches $V_{\gamma }$, so it stops charging the capacitor $0.7\text{ V}$ short of the ideal, leaving the clamped peak offset by that same $0.7\text{ V}$.

Clamping adds the same number to every point (a rigid vertical slide, spacing preserved); clipping replaces points past a threshold with a flat value (spacing crushed to zero there).

A Zener conducts forward at $V_{\gamma }$ and reverse-breaks down at $V_Z$, so a single Zener (or back-to-back pair) sets both clip limits — one device does what two ordinary diodes plus batteries would.

The diode chooses which polarity conducts; flipping it swaps whether the top or the bottom of the wave gets clipped. Orientation is the sign of the whole answer.

Almost nothing. Clipping starts only at $V_{\gamma }\approx 0.7\text{ V}$, and the peak never reaches it, so the diode stays OFF the entire cycle and $v_o\approx v_i$.

Distorted / not yet clamped. The offset only exists after the cap has seen a full peak; the first cycle is a transient and the steady clamped waveform appears from the second cycle onward.

The capacitor discharges noticeably between peaks, the offset sags, and the "clamp" tilts and wobbles instead of holding a clean flat baseline — clamping effectively fails.

If the diode is oriented to pass positives, it stays reverse-biased the whole time, conducts nothing, and $v_o\approx 0$ for the entire waveform.

The peak never drives the diode past $V_{\gamma }$, so the capacitor barely charges and there is almost no DC shift — the clamper needs a swing bigger than the diode's turn-on to work.

No clipping at all. Neither diode reaches its threshold, both stay OFF, and the output equals the input — the "band" is wider than the signal, so nothing is removed.