Capacitor and diode curcit for ac to dc voltage

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SUMMARY

The discussion focuses on the behavior of a capacitor and diode circuit used for converting AC to DC voltage. It is established that the diode conducts current when the voltage exceeds 0.7V, allowing the capacitor to charge. Once the voltage falls below this threshold, the capacitor discharges, leading to a variation in the DC voltage over time. The voltage droop is determined by the RC time constant, which is a function of the load resistance (R) and the capacitance (C).

PREREQUISITES
  • Understanding of diode forward voltage drop (0.7V)
  • Knowledge of capacitor charging and discharging principles
  • Familiarity with RC time constant calculations
  • Basic concepts of AC to DC conversion circuits
NEXT STEPS
  • Study the effects of load resistance on capacitor discharge rates
  • Learn about different diode types and their voltage drop characteristics
  • Explore advanced capacitor filtering techniques in power supply design
  • Investigate the impact of varying capacitance values on circuit performance
USEFUL FOR

Electronics engineers, hobbyists designing power supply circuits, and students studying AC to DC conversion methods.

nokia8650
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http://img42.imageshack.us/img42/2461/49889005.th.jpg

My question is, why does the dc voltage vary with time in this way? Ply it is something to do with the diode allowing current to flow when it has 0.7V or more across it, allowing the capacitor to charge, and when the voltage drops to below this, the capacitor discharges, however could someone please provide a more comprehensive explanation?

Thanks a lot in advance.
 
Last edited by a moderator:
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nokia8650 said:
http://img42.imageshack.us/img42/2461/49889005.th.jpg

My question is, why does the dc voltage vary with time in this way? Ply it is something to do with the diode allowing current to flow when it has 0.7V or more across it, allowing the capacitor to charge, and when the voltage drops to below this, the capacitor discharges, however could someone please provide a more comprehensive explanation?

Thanks a lot in advance.

Your explanation is correct. The droop between the power input part is at the RC time constant specified by the load R and the storage C.
 
Last edited by a moderator:

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