ASVAB (Armed Services Vocational Aptitude Battery)Electronics Information (EI)Medium
A technician is troubleshooting a power supply and measures a pulsating DC voltage at the output of a full-wave bridge rectifier before the filter capacitor. Which component is responsible for smoothing this pulsating DC into a more stable DC voltage?
- AFilter capacitor
- BResistor
- CTransformer
- DDiode
Show answer & explanationAnswer & explanation
Correct answer: A. Filter capacitor
After rectification, the DC voltage is pulsating. A filter capacitor is specifically used to smooth out these pulsations (ripple) by charging during the peaks and discharging through the load during the valleys, thereby providing a more stable DC output.
Why the other options are wrong
- B. Resistors limit current and dissipate power, but do not smooth pulsating DC.
- C. Transformers step up or step down AC voltage, but do not smooth DC.
- D. Diodes are used for rectification, converting AC to pulsating DC.
Filter Capacitor
A capacitor used in power supply circuits to reduce ripple voltage, converting pulsating DC from a rectifier into a smoother, more stable DC output.
- Placed after the rectifier.
- Charges during voltage peaks, discharges during valleys.
- Reduces ripple, provides smoother DC.
Memory trick: Capacitor Creates Calm Current.