Power supplies tutorial

Power supplies tutorial.  

 

//This article was gathered to develop a power supply for a Paia 2720 VCO.

 

Requirements:

 

1.) Dual bi-polarity 9 VDC

2.) Dual bi-polarity 5 VDC

3.) Variable 0 to 5 VDC

4.) 18 VDC

Step 1 The actual circuit

As I only have a couple of modules of the 2720 I thought I would build a simple power supply to test them.  I didn't want to use transformers so the project became a good refresher of how power supplies work in general. 

Hope you find this useful or educational.  Most of the information I present here is web based, with a little experience thrown in for good measure. 

Comments

[MROHM]

Your Right!!! The Zener should be 10volts,Why You Ask?? Vbe= ,7 volts so the Voutput would be Vo= Vz- Vbe or Voltage Output = Zener Voltage- Voltage base to emitter====== 10v- .7v= 9.3v I hope this helps !!

[Orbitalgun]

These are really great modifications to the circuit Mr Ohm! Thanks for bringing them to light.

[MROHM]

Hi MR Orbitalgun This is what makes Electronics Fun,,, when we can already Improve on a otherwise outstanding circuit!! I must go now,,,I smell my Weller Heating up!!! PS*** Nice Instructable !!!

[MROHM]

Actually I designed a Circuit just like this a few years ago,,I used Tip41 and Tip42 Transistors,, Heat sinked them to a Chassis and was able to get 1 amp output from each rail, I also used a 3 amp transformer to provide 1amp headroom for this circuit.Also I used a 100K Resistor for R1 and R2 to prevent loading on the Op Amp. I also used a 741 Op Amp which is available Everywhere,, So if I pushed This circuit ,,,1 amp per rail would be a 2 amp output,,,but the Transformer was rated 1 amp higher(3 amps) to provide the necessary headroom and to prevent Mr.transformer from overheating!!! By Providing These Minor Adjustments the user can have a Cost effective, Near Lab Quality piece of Test Gear which Would be a Welcome Addition To Any Test Lab!!!!

[ankitgarg2005]

how can I double a 6V 4.5Ah battery into 12v battery with 2A current or more.

[Orbitalgun]

You could do this a variety of ways... If you had a second battery you could use them as a 12v source by putting them in series, or you could use a simple voltage doubler( google voltage doubler), You might even consider using a charge pump.

[ankitgarg2005]

I need to convert a single 6v battery to 12v with more then 2A current . Voltage doubler available on websites gives only 100mA or 200mA. current.

[Orbitalgun]

Battery?! Forget the voltage doubler use a charge pump instead.

[aniccame]

This article was very useful to me. Here's the circuit in practice, with some additional pictures and part numbers:

http://electropub.wordpress.com/2011/04/16/15v-dual-power-supply/

[Orbitalgun]

Thank you for looking over this, my first instructable. I 'm glad to hear it pointed you in the right direction. Also, I read your article and it was very clean and forth right. Thumbs up!