We r given a theoritical project on Linear regulator power supply.
I need advice from this board regarding the same.
The input is as usual 230V,50Hz and output is -5V,1.5A

we r supposed to use a vol regulator IC in last stage, which is be IC 7905.
the architecture will be

(input)-(LPF)-(Transformer)-(rectifier)-(Filter)-(Vol regulator)-(output)

few details which i have are
* X'mer is in centre tapped supply.
*use 79XX series vol reg.
*use heat sink

what i need to know
*What are the filters i am using at various stages and why? or why am i not using other filters?
*what rectifier,transformer,vol reg is most suitable and why?


the actual problem statement is
Q) Design a LPRS with following specifications
output -5V,1.5A
mains -15% to 10%
Ripple factor 10%
Find load and line regulations
also consider using miniature CKT breaker,MCB,Fuse,heat sink,MOV.
F should remain constant throught the supply.
Simulate it on multisim.
--------------------------------------------------------------
i request you to please add if possible the following items
*ckt diag
*componets u r suggesting
*cost of component(INR)
*data sheet/features of component used.

we have to just simulate and submit the report asap.
i feel quite helpless as i have no experience of handling such electronics project. so i will need ur help so that i can learn the techniques and start designing myself.
I will sincerely appreciate if you answer keeping in mind that i am trying to be self dependent.

 

You seem to be contradicting yourself. you say you are trying to be self dependent but then ask for someone to provide you with a finished project including the cost of components and datasheets. Which bit do you intend doing yourself? Have you done any research or downloaded any datasheets?

 

We r given a theoritical project on Linear regulator power supply.
I need advice from this board regarding the same.
The input is as usual 230V,50Hz and output is -5V,1.5A

we r supposed to use a vol regulator IC in last stage, which is be IC 7905.
the architecture will be

(input)-(LPF)-(Transformer)-(rectifier)-(Filter)-(Vol regulator)-(output)

few details which i have are
* X'mer is in centre tapped supply.
*use 79XX series vol reg.
*use heat sink

what i need to know
*What are the filters i am using at various stages and why? or why am i not using other filters?
*what rectifier,transformer,vol reg is most suitable and why?


the actual problem statement is
Q) Design a LPRS with following specifications
output -5V,1.5A
mains -15% to 10%
Ripple factor 10%
Find load and line regulations
also consider using miniature CKT breaker,MCB,Fuse,heat sink,MOV.
F should remain constant throught the supply.
Simulate it on multisim.
--------------------------------------------------------------
i request you to please add if possible the following items
*ckt diag
*componets u r suggesting
*cost of component(INR)
*data sheet/features of component used.

we have to just simulate and submit the report asap.
i feel quite helpless as i have no experience of handling such electronics project. so i will need ur help so that i can learn the techniques and start designing myself.
I will sincerely appreciate if you answer keeping in mind that i am trying to be self dependent.

Hi,
I have attached the circuit.
The transformer should be a 230v to 6v transformer. No need for center tapping. No need for LPF as this is a linear power supply. The diode used is 1N5408, 3A, 1000v. C1 and C3 are 1000uF 50v capacitors, although you can use 16v caps. C2 and C4 are 0.1uF 50v ceramic caps. The IC is a fixed negative voltage regulator: 7905 and should be mounted on adequate heatsink.
The fuse is a 1A standard fuse connected to the input. No need to use ckt breaker or MOV as this is a linear power supply.
You can look up the datasheets at:
www.datasheetcatalog.com
or
www.datasheet4u.com


The parts I suggested are those that I have used are running successfully. Instead of 50v caps, you can use 16v caps. The diode can be 1N5401 as well.

Thanks.

 

Tahmid,
This appears to be a homework assignment, with some rather specific requirements.

It isn't a good idea to hand students a completed schematic, because then they won't have applied any effort themselves in working out the problem, so they will not learn anything.

Your schematic does not address numerous requirements that the OP has been given, so it is not really suited for their purpose.

 

We (have been) given a theoretical project on Linear regulator power supply.
I need advice from this board regarding the same.
The input is as usual 230V,50Hz and output is -5V,1.5A

we (are) supposed to use a vol(tage) regulator IC in (the) last stage, which is be IC 7905.
the architecture will be:

(input)-(LPF)-(Transformer)-(rectifier)-(Filter)-(Vol regulator)-(output)

(The) few details which i have are:
* Transformer is in centre tapped supply.
*use 79XX series voltage regulator.
*use heat sink

What I need to know:
*What are the filters i am using at various stages and why? or why am i not using other filters?

You use a low-pass filter prior to the transformer in order to filter out line transients such as may be caused by heavy motors on the same mains line switching on and off, or lightning. Without such filtering, the transformer and subsequent parts may be subjected to voltages that may damage them. A "pi filter" is one way to reduce or eliminate such transients.

After the rectification of the AC output of the transformer, a filter is required to remove the ripple component. Often, this is simply a large capacitor to remove the low frequencies paired with a small capacitor to remove the high frequencies.

*what rectifier,transformer,vol reg is most suitable and why?
The transformer, rectifier and voltage regulator selection are all interrelated.
A pair of standard rectifiers such as a 1N4001 could be used, but one must keep the forward voltage in mind. At 1A, a 1N4001 will have a Vf of 1.1V. If one used a Schottky diode such as a 1N5817 will have a Vf of 0.45v at the same current. You should explore other rectifiers, both Shottky and standard rectifiers. Download the datasheets, so that you have hard evidence of their performance.

All voltage regulators have a parameter known as "dropout voltage" - that is the minimum difference between the input voltage and the output voltage. 79xx series regulators have a 1.1v dropout with an output current of 1A. The datasheet I have does not specify dropout with higher output currents, but adding another 0.6v would be a decent guess.

So, you need to total up your rectifier's Vf, the dropout voltage of the regulator and the voltage drop across the low pass filter to get the minimum output voltage required of the transformer. Don't forget that it has to operate with the mains up to 15% lower than normal.

You can obtain datasheets on various semiconductors at places such as Alldatasheet.com, Datasheetcatalog.com
You can use vendor's search engines to find parts.
Farnell in the UK
Digikey.com
Mouser.com
Newark.com
are just a few.

Many provide datasheets along with the price.
Make sure you record the manufacturer's part number alongside the vendor's part number, along with the vendor name and price.