voltage regulators

Ask questions about projects relating to: aerodynamics or hydrodynamics, astronomy, chemistry, electricity, electronics, physics, or engineering

Moderators: MelissaB, kgudger, Ray Trent, Moderators

voltage regulators

Postby sharmaluv » Sun Dec 09, 2007 11:16 pm

can someone help me out wid my project.actually its a part of my project.........can anybody help me wid 220v to 5v dc voltage regulator..............vat will be the materials required and the circuit design........?????????
sharmaluv
 
Posts: 3
Joined: Sun Dec 09, 2007 10:44 pm

Postby Craig_Bridge » Mon Dec 10, 2007 5:43 am

I don't understand enough about what you really need.

1) Are you talking about a power supply that will start with 220 VAC and will deliver 5 VDC with some current capabilities? If you are, then you need to specify how many Amps or Milli-Amps your load requires. Typically, these are things that are purchased because there are safety considerations involved with anything that attaches to the power grid.

2) Are you talking about an adjustable output power supply that can provide a controlled voltage between 5 VDC and 220 VDC at some current rating? If you are, then in addition to the current rating, you need to provide some details on what the source of power is. Adjustable power supplies with a 44:1 range tend to be expensive because they are inherently inefficient and have to dissipate a lot of power.

Why don't you describe a bit more of what your real project is as this aspect appears to be something that is required to make something else work.

If you just need 5 VDC for some electronic circuit project on a breadboard there are several inexpensive approaches:
1) 4 NiMH battery cells in series will supply about 5 volts.
2) A 6v battery with a silicone diode will supply about 5.3 volts.
3) A 6v battery with a 7805 integrated circuit will supply 5 VDC. Depending on the current requirements, you may need multiple batteries in parallel and a heat sink. Note: The leads on a 7805 three lead regulator are larger than what can be used directly in the holes in the plastic project bread boards designed for 24 AWG or smaller.
-Craig
Craig_Bridge
Expert
 
Posts: 1297
Joined: Mon Oct 16, 2006 11:47 am

Postby sharmaluv » Wed Dec 12, 2007 10:28 pm

thkns craig for ur valuable guidance...but let me tell u that i need a circuit that will gedcnerate 5Vdc outt of the power supply...........in simple words i hav a younger bro......and i want to demonstrate to him how hthis simple circuit works out by practically implementing it.............i.e. by designing it on a pcb.................now if u fully understand what i require then plz tell me of the components required..............
sharmaluv
 
Posts: 3
Joined: Sun Dec 09, 2007 10:44 pm

Postby Craig_Bridge » Thu Dec 13, 2007 9:33 am

I'm help get you started by providing some information for you to research; however, be advised that this is NOT a good science fair project because it is a demonstration and not a scientific investigation. I'm not saying you can't learn a lot; however, it will not be using the scientific method so it won't count as science.

CAUTION: You need adult supervision by somebody who understands electricity or you need to find a pre-packaged unit listed by UL/CSA/TUV (or other safety testing laboratory) that contains a power cord and transformer that will supply low voltage AC power.

These units are essentially a power cord, a fuse, and a transformer in a fully double insulated housing to prevent access to the line voltage. If you build your own, you need to understand the safety design aspects of providing your own housing and isolation between line voltage and secondary. This is beyond what I'm able to provide. If you build your own, you need somebody supervising that understands these aspects.

The secondary circuit of the transformer unit you buy or build should provide somewhere between 9 and 12 VAC.

Look up half wave power rectifier and full wave bridge rectifier circuits. You will need one of these as the next stage. This will convert alternating current to either half wave or "folded wave" direct curernt. There should be some wave diagrams somewhere on some related web site that describe this.

Look up filter capacitors for DC power supplies. You will need one of these as the next stage. What this does is to "integrate" or smooth out the wave. You need to do a little research into time constants and current equations to size the capacitor. Tantalum are probably best for this application. Electrolytic were used before tantalum were commonly available. You need to understand working voltage to choose the correct one as well.

Find an application guide for the 7805 three leg voltage regulator and read up about it. This will be the next stage. You need to understand power disapation and heat sink requirements.

The last stage is again a filter capacitor; however, in this case it will be a high frequency filter. Something like a 0.001 to .1 ufd. Film are the best for this application. Ceramic and mica are older varieties that were used before film.

I hope you have mastered soldering skills and other construction techniques. Have fun researching.
-Craig
Craig_Bridge
Expert
 
Posts: 1297
Joined: Mon Oct 16, 2006 11:47 am

Re:

Postby copyme » Thu Nov 25, 2010 4:13 am

Craig_Bridge wrote:I don't understand enough about what you really need.

If you just need 5 VDC for some electronic circuit project on a breadboard there are several inexpensive approaches:
1) 4 NiMH battery cells in series will supply about 5 volts.
2) A 6v battery with a silicone diode will supply about 5.3 volts.
3) A 6v battery with a 7805 integrated circuit will supply 5 VDC. Depending on the current requirements, you may need multiple batteries in parallel and a heat sink. Note: The leads on a 7805 three lead regulator are larger than what can be used directly in the holes in the plastic project bread boards designed for 24 AWG or smaller.


Thanks i was reallu in need of these instructions.
copyme
 
Posts: 1
Joined: Thu Nov 25, 2010 4:09 am
Occupation: Student: 9th grade
Project Question: n/a
Project Due Date: n/a
Project Status: I am just starting


Return to Grades 9-12: Physical Science

Who is online

Users browsing this forum: Bing [Bot], Yahoo [Bot] and 6 guests