Sources, diodes and a rectifier
Use sine and pulse sources and simulate a half-wave rectifier with a smoothing capacitor.
Real signals are rarely a bare DC value. LTspice voltage sources can generate the common ones, set through right-click > Advanced.
- SINE(Voffset Vamp Freq): a sine wave, e.g. SINE(0 10 50) is 10 V peak at 50 Hz.
- PULSE(V1 V2 Tdelay Trise Tfall Ton Tperiod): clocks and square waves.
- PWL(t1 v1 t2 v2 ...): any shape you describe point by point.
Half-wave rectifier
- Run and plot V(IN) and V(OUT). Without the capacitor the output is only the positive half-cycles.
- With C1 present, the capacitor holds the peak between half-cycles, leaving a ripple.
- Notice the peak is about 0.6 to 0.7 V below 10 V: that is the diode forward drop.
- Change C1 to 10u and then 470u and compare the ripple. Larger C, smaller ripple.
Ripple is approximately I / (f x C). Use it to size the capacitor, then confirm it in the simulator.