Why do we need DC power supplies in electronic circuits?
To convert AC β DC safely and reliably
Electronic circuits require steady DC voltage for stable operation.
What does a DC power supply provide for electronic components?
- Stable operation
- Noise-free signals
- Reliable biasing for amplifiers and logic circuits
Most semiconductor devices require constant polarity and fixed voltage.
What are the blocks in a regulated DC power supply?
- AC Input
- Transformer
- Rectifier
- Filter
- Voltage Regulator
- DC Output
The blocks work together to convert AC to clean, stable DC voltage.
What is the function of a transformer in a DC power supply?
Changes AC voltage level and provides isolation from mains
Typically steps down 230 V to a lower AC voltage.
What is the role of a rectifier?
Converts AC into pulsating DC using diodes
Essential for transforming the AC output from the transformer.
What does a filter do in a DC power supply?
Reduces AC ripples and provides smoother DC output
It smooths the pulsating DC output from the rectifier.
What is the purpose of a voltage regulator?
Maintains constant DC voltage despite changes in input or load
Ensures stable output for the powered device.
Name the types of rectifiers.
- Half-Wave Rectifier (HWR)
- Full-Wave Rectifier (FWR)
- Bridge Rectifier
Each type has different configurations and efficiencies.
How does a half-wave rectifier operate?
Uses one diode; conducts during positive half-cycle, blocks during negative half-cycle
Outputs only positive pulses (pulsating DC).
What is the formula for average DC voltage in a half-wave rectifier?
πππ = ππ/Ο
Where ππ is the peak voltage.
What is the ripple factor (r) for a half-wave rectifier?
r = 1.21
Indicates the amount of ripple in the output.
Describe the operation of a full-wave rectifier.
Uses two diodes; both halves of AC waveform are utilized
Outputs continuous positive pulses, resulting in smoother DC.
What is the formula for average DC voltage in a full-wave rectifier?
πππ = 2ππ/Ο
Provides a higher average DC voltage compared to HWR.
What is the ripple factor (r) for a full-wave rectifier?
r = 0.482
Indicates reduced ripple compared to half-wave rectification.
How does a bridge rectifier function?
Uses four diodes; conducts two diodes per half-cycle
Provides a constant output current without needing a center tap.
What is the formula for average DC voltage in a bridge rectifier?
πππ = 2ππ/Ο
Similar to the full-wave rectifier.
What is Peak Inverse Voltage (PIV) in a bridge rectifier?
Maximum reverse voltage a diode can withstand without damage
Each diode has a PIV lower than that of a full-wave center-tap.
Why is a filter needed in a DC power supply?
To smooth pulsating DC output from the rectifier
Filters reduce ripples to provide steady DC.
Name the types of filter circuits.
- Capacitor Filter
- Inductor Filter
- LC Filter
- Ο (Filter)
Each type serves to smooth the output in different ways.
What is the Ripple Factor (r)?
Ratio of RMS value of AC component to DC component
r = πππ/πππ.
What does efficiency (Ξ·) measure?
Ratio of DC output power to AC input power
Ξ· = (πππ/πππ) Γ 100%.
What is the purpose of a UPS (Uninterrupted Power Supply)?
Provides power during mains failure
Prevents data loss or circuit shutdown.
What are the types of UPS?
- Offline UPS
- Online UPS
Each type has different operational characteristics.
What is the purpose of an SMPS (Switched-Mode Power Supply)?
Converts power efficiently using high-frequency switching
Advantages include smaller size and higher efficiency.
