The waveform generator WG is set to give a sine wave of 1kHz. It is monitored by oscilloscope channel A1. The signal after the diode is monitored by A2. The observed waveform will be a bit noisy without the load resistor, connecting a 1k resistor gives a clean rectified waveform. The voltage drop across the diode is clearly visible. Connect different values of capacitors to view the filtering effect.
|Wiring Diagram||Photograph of the experimental setup|
|Screen shot of the oscilloscope program showing input and output of half wave rectifier. 1N4148 diode at 1000Hz and 1kOhm load resistor.|
Every diode has a junction capacitance that acts like a capacitance connected in parallel to the ideal PN junction. Junction capacitance of 1N4148 is only 4pF but 1N4007 has a junction capacitance of 20pF. The rectified output, without external load resistor, for 1N4007 is shown below. The 1MOhm input impedance of channel A2 will be always present.
p = eyes17.eyes.open()
from pylab import *
t,v, tt,vv = p.capture2(500, 20) # captures A1 and A2
plot([0,10], [0,0], 'black')
plot(t,v,linewidth = 2, color = 'blue')
plot(tt, vv, linewidth = 2, color = 'red')
|Python program to study half wave rectifier||Output of the code|