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Rectifier Troubleshooting

The scope shows the waveform at TP1(Red) and the output of the rectifier (Green). The animation shows the effect of varying C from 1.0 uf to 1000 uf on the ripple voltage of the rectified output. 

Vert: 2V/division   Horiz: 5 msec/division

Use above as Base Line when troubleshooting problems below.

Possible Faults 

            1. Capacitor Open

            2. Capacitor Leaky

            3. Capacitor Shorted

            4. Resistor Open

            5. Diode CR1 Shorted

            6. Diode CR1 Open

            7. Diode CR2 Shorted

            8. Diode CR2 Open



Failure 1
Ripple Voltage too High

Vert: 2V/division   Horiz: 10 msec/division



Failure 2
Ripple Voltage to High

Vert: 2V/division   Horiz: 10 msec/division



Failure 3
Ripple very low. Why?

Vert: 2V/division   Horiz: 10 msec/division



Answers Below





Answers Below



Answers Below



Answers Below 1

Failure 1:  Capacitor Leaky (2)




Answers Below 2

Failure 2: Diode CR1 Open (6) 



Answers Below 3

Failure 3:1k resistor open (4) 
The ripple voltage was very low which is generally a good thing; however, circuits don't improve spontaneously. Capacitors don't increase over an order in magnitude due to failure. Here, no ripple indicates no load.  Even high amperage regulated outputs generally have ripple between 10mV and 100 mV.   

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