5.0 V regulated power supply

[timy]

I need assistance in constructing a 5.0 regulated power supply and i do not even know where to start. I am not allowed to use a prebuit regulator and must therefore construct one myself. All ideas or suggestions for design, materials, and circuitry would be highly appreciated.

Thank you!

 

[IanP]

A voltage regultor can be build in so many different ways .. here are examples base on BJTs and Zener Diode + Opamp ..
Of course in both cases you will need unregulated power: **broken link removed**

Regards,
IanP

 

[nguyennam]

How about the current needed.

In general, the L7805 IC is the best solution, it can provide up to 1.5A (depending on package type), has internal overcurrent and overheat protect.

You will need only:
- 1 transformer of 7.5 to 9VAC output with appropriate current.
- 4 diodes 1N4004, if current not exceed 1A
- 1 cap of 1000uF/16V for the input pin of L7805
- 1 cap of 100uF/10V for output pin of L7805
- 1 cap of 0.1uF for the output of L7805
- 1 L7805 itself.

That is all.

Circuit diagram see from L7805 datasheet.

nguyennam

 

[siongboon]

Use 7805 IC. Should be quite easy.
Try this website for DC-DC regulator using LM2576.
It has alot of advantage over 7805 regulator.
**broken link removed**

 

[roykyn]

use LM317 ...u can get variable power supply

 

[amriths04]

try using zener diodes with different reverse breakdown potentials and connect them in such a way that when you turn the knob it would connect to the needed zener diode. so you will be having a constant output voltage as long as the zeners are reverse biased.

make sure that the zeners' rev brk voltages are the necessary constant voltages that you might want.

regards,
AMRITH.S.

 

[jonw0224]

I am not allowed to use a prebuit regulator and must therefore construct one myself.

I don't think the answer use a "regulator IC" like LM317, L8205, or LM2576 makes sense as a response to this post. timy, what Ianp suggests is a good answer for a realitively wide range (limited by the series transistor) of load currents.

If you need a high current (or high efficiency) solution, you need to design a switching regulator. That is more complicated.

-jonathan