A SlideShare about Diode bridge rectifier

1. 1
a Bridge Rectifier Work

2. 2
•Rectifier Circuits :
 Rectifiers convert ac into dc
 Bridge Rectifier
 Looks like a Wheatstone bridge. Does not require a enter tapped
transformer.
 Requires 2 additional diodes and voltage drop is double.

3. Diode Bridge Rectifier Basics
• A diode bridge rectifier is a device for converting AC,
or alternating current electricity into DC, or direct
current. AC electricity goes from positive to negative
constantly, whereas DC always flows in the same
direction. AC electricity is more efficient to transmit
and easier to convert into different voltages, so
power is transmitted from the station to your house
as AC. However, most appliances need DC current to
run. A diode bridge rectifier is the most common
type of power supply used to provide this current.
3

4. 4
120/25V
Transformer
120V
Variac
Important − never connect a DBR directly to
120Vac or directly to a variac. Use a 120/25V
transformer. Otherwise, you may
overvoltage the electrolytic capacitor
Diode Bridge Rectifier
(DBR)
+
–
+
≈ 28Vac rms
–
1
4
3
2
Equivalent DC load
resistance RL
+
≈ 28√2Vdc ≈ 40Vdc
−
Iac
Idc
Be extra careful that you
observe the polarity markings
on the electrolytic capacitor

5. 5
AC and DC Waveforms for a Resistive Load
Vac
-40
-20
0
20
40
0.00 8.33 16.67 25.00 33.33
Milliseconds
Volts
With a resistive load, the ac and dc current waveforms
have the same waveshapes as Vac and Vdc shown above
+
Vac > 0
–
1
2
+
Vdc
– –
Vac < 0
+
4
3
+
Vdc
–
Vdc
-40
-20
0
20
40
0.00 8.33 16.67 25.00 33.33
MillisecondsVolts

6. 6