# Bridge rectifier regulated lab power supply circuit schematics

A good regulated AC to DC power supply circuit is essential for any electronic hobbyists and electronic students to do thier electronics hobby projects. Also a bridge rectifier power supply is one of the introductory circuits for beginners. Firstly we need to know what is a bridge rectifier? A rectifier circuit employs the conversion of AC voltage to DC voltage. Full wave bridge rectifiers have the benefit that they transfer both half cycle of AC input into DC output and also efficiency is two times greater than that of half wave rectifier. Bridge rectifier circuits are put into practice using diodes such as 1N4001, 1N4007 etc.

Below is the circuit schematic of rectifier regulated power supply using 78XX voltage regulator IC. 78XX is a positive voltage regulator and available at different output voltages as 7805 for 5V, 7809 for 9V, 7815 for 15V etc. Hence you can implement power supplies for required voltages, that is 5V, 9V or 15V as you like. Solder this regulated power supply circuit on PCB and enclose it in a suitable case, definitely it will  help you for future circuit projects.

## Components required

1. Step down transformer (1A, 230V or 110V primary secondary should be your choice like 6V, 9V etc).
2. Diodes x 4 (1N4001 for low power 1N4007 for moderate power)
3. Capacitor (470µF, 16V)
4. Voltage regulator IC 78XX (Here we have used 7805)

## Working

• Circuit consists of 4 parts: Step down transformer, bridge rectifier, capacitor filter and voltage regulator IC.
• The transformer step downs the high voltage AC to a low voltage AC.
• During the positive half cycle of secondary voltage, diodes D2 and D3 are forward biased and diodes D1 and D4 are reverse biased, now the current flows through D2–>Load–>D3
• During the negative half cycle of the secondary voltage, diodes D1 and D4 are forward biased and diodes D2 and D3 are reverse biased Now the current flows through D4–>Load–>D1
• In both the cycles load current flows in same direction, hence we get a pulsating DC voltage across the points B-B’.
• The pulsating content are called ripples and a filter capacitor is used to remove the ripples from pulsating DC.
• When the instantaneous values of pulsating DC voltage increases, the capacitor gets charged up to peak value of the input.
• When the instantaneous values of pulsating DC voltage decreases, the stored voltage in the capacitor reverse biases the diodes D2 and D4. Hence it will not conduct, now capacitor discharges through the load. Then voltage across the capacitor decreases.
• During the next cycle, when the peak voltage exceeds the capacitor voltage, diode D2 or D4 forward biases accordingly, as a result capacitor again charges to the peak value. This process continues. Hence we get almost smooth DC voltage as shown.
Brown color indicates pulsating DC and Red color is the filtered DC voltage.
• Then the filtered voltage is applied to the input of 7805 voltage regulator IC, it in turn regulates the voltage for line and load fluctuations.
Brown color indicates capacitor output DC and Red color is the regulated  5V DC  from 7805.

Related Circuits:

## Note:

Use 6V secondary transformer and 7805 for 5V supply, 9V secondary transformer and 7809 for 9V supply.

## 22 thoughts on “Bridge rectifier regulated lab power supply circuit schematics”

1. Anonymous says:

can I use a 35v capacitor in place of 16v

• Hi
You can use any voltage rated capacitor grater than the the working voltage (Transformer secondary voltage)

2. hi admin, i want to make 0-40v 3a regulated power supply …please give some hint.

3. ricocer says:

hi admin i want to build a time delay circuit can you provide me a circuit for that thank you and more power

4. Dashrath says:

Hi sir mail me the complete calculation with an example for power supply designing using bridge rectifier and regulator 7805.

5. Jasdeep says:

Hi may i have the schematic for a dc power supply with a fixed 9v output using bridge rectifier?
Thank you

• Yaseen says:

Hi Jasdeep
You can use the above schematic by replacing 78xx with 7809.

• Jasdeep says:

Thank you Yaseen

6. Andres Barrios Jr says:

Hello! Sir, I’m trying to monitor a ac motor using the 30amp acs712 hall current sensor that converts motor amp to a 0-5 Vout signal. I would like to change that signal to DC using a full wave rectifier with a filtered to smooth out the output signal. Can you Help with components

7. Andres Barrios says:

Hello! Sir, I’m trying to monitor a ac motor using the 30amp acs712 hall current sensor that converts motor amp to a 0-5 Vout signal. I would like to change that signal to DC using a full wave rectifier with a filtered to smooth out the output signal. Can you Help with components

8. Amelia says:

may I have the schematic diagram for dc power supply with fixed 5V using half-wave rectifier. Thank you

• Yaseen says:

Hi Amelia
To get half wave rectifier remove three diodes (1,3,4) and connect A’ to B’ .
To get +5V replace 78XX with 7805 Regulator IC.

9. Balvinder says:

Hi there. i’m looking a the schematics for dc power supply with a fixed 5v output using a full wave rectifier. It would be great if you can help me 🙂

• Yaseen says:

Hi Balvinder
Use above schematic by replacing 78xx with 7805, then you will get fixed +5V.

10. Firoza Patel says:

Hello
I am working with a 4.5-5 volt ac supply and want a 5 volt dc supply. Can I have the schematic and component models for it using a full wave bridge rectifier?
Thank you

11. Jon Bryant says:

Hi
Im trying to rectify 110V AC to 110V DC from a 240 to 110V transformer at 50 Hz i plan on using a bridge rectifier but I am stumped by the Cap size I require to smooth the ripple.
Could you please give me an idea of the required Cap 10% ripple would be ok, Looking at your circuit at the top of the page it apears you have designed the very circuit i require, butr you have used a 16V cap would this voltage work or would it need to be a 100V
Many Thanks

12. noman says:

hi admin how will i design this capacitor with equation and can i use zener in place of 78xx

13. Bryan says:

Sir,
Would it be possible to create a schematic to convert 5 volts AC (400 Hz) to 5 volts DC?