DC power supply

[Rleo6965]

Here's another circuit for individual output

 

[Rleo6965]

you mean I have to use 4 potentiometer and adjust them in proper position to get 5V, V , 9V and 12V respectively at the outputt ? Or replaceed it with fixed value resistor ?

Much simpler if you buy variable resistor to have accurate dc output.

Long time I have not visit here.
I'm busy DIY rebuilding my junk Mitsubishi 1.3L 4G13 engine. Same engine use by Proton Wira car there in Malaysia. Already finished rebuilding. Just waiting for mounting in my car.
I can now call myself Mechanic.

 

[vick5821]

I want one terminal output only. And not 4 output. based on your latest circuit, it consists of 4 seperate output terminal ?

 

[Rleo6965]

It's your choice to select the first circuit using LM317 Variable voltage regulator. It's simpler. Less component. More accurate. Be sure to place filter capacitors near the IC regulator and important don't forget the heatsink. Use higher gauge wire to wire Vout to Terminal Screw and ground wire to avoid voltage drop.

 

[vick5821]

I plan to do like this. I use switch to control the fixed output voltage I want like 5V6, 6V, 9V and 12V. Besides, I plan to have another option where I can adjust the output voltage I want. And based on your firsr schematic, need to use 4 varaible resistor and adjust them each in proper position to get the output I want isnt that ? I think Cocacola idea is better by using DPDT switch. However, I think I am able to modify the switch connection to make it become a DP4T switch right ?

 

[vick5821]

Lateset sketch. Is it ok ?

@CocaCola, is this ok you think ?? Will it be any mistake ?

Thank you

 

[Rleo6965]

Can you show me the diagram in your mind. I don't know about DP4T. First time encounter this electronic term.

 

[vick5821]

This was suggested by @CocaCola. I also not sure. It means Double pole 4 Throw.?? Got such switch ?

 

[Rleo6965]

Big mistake. Your using 2 separate DPDT and both output tied together. In either switch position upper switch output ( +5V or 6V) will short lower switch output ( 9V or 12V ). Your fixed voltage regulator will be damage together with your load.

Avoid using switch on Vin. Tie them together and and only fixed regulator have output connection will consume current. Other fixed regulator will not consume dc current even its Vin was tied together with other Vin.

 

[Rleo6965]

This was suggested by @CocaCola. I also not sure. It means Double pole 4 Throw.?? Got such switch ?

I got it. It's a 2 gang 4 position rotary switch. I don't think you can buy high current contact. This was only use for low voltage signal selection. I think this is the one that that short first the adjacent contacts before breaking the connection and make another contact connection. This is no good for switching output voltage.

 

[CocaCola]

I got it. It's a 2 gang 4 position rotary switch. I don't think you can buy high current contact. This was only use for low voltage signal selection. I think this is the one that that short first the adjacent contacts before breaking the connection and make another contact connection. This is no good for switching output voltage.

They make 'higher' current ones and they make slide as well as rotary ones that don't short...

Can't say if this particular one shorts or not but it's only being used an example...

http://www.mouser.com/ProductDetail/CW-Industries/G-1138S-1110/?qs=GMJVKvQynaA5j1p7wbo0ww==

Here is a 6A rated 5 position non-shorting rotary...

http://www.mouser.com/ProductDetail/CK-Components/MB00L1NZQD/?qs=J2dJc02fMkplyVq%2b4Icc2Q==

 

[Rleo6965]

@CocaCola

Thanks for enlighten me.

 

[vick5821]

Big mistake. Your using 2 separate DPDT and both output tied together. In either switch position upper switch output ( +5V or 6V) will short lower switch output ( 9V or 12V ). Your fixed voltage regulator will be damage together with your load.

Avoid using switch on Vin. Tie them together and and only fixed regulator have output connection will consume current. Other fixed regulator will not consume dc current even its Vin was tied together with other Vin.

If I switch to output throw, it will output 5V isnt that ? and others regulator wont have any Vin so not activated. I am using two DPDT switch here

 

[Rleo6965]

That's another problem. Even fixed regulators have no Vin but their Vout was connected to another Vout of other fixed regulator. This will also damages the ic regulator. It's just like placing input voltage to Vout pin.

 

[Rleo6965]

I modified my first circuit so you can use 1P4T non shorting high current rotary switch.
Vin still tied together and does not use switch.

 

[vick5821]

Will this be a problem if the Vin is always connected to the power if the voltage rating is not being selected ? Cause from your circuit, when I select 5V, the others regulator like 7806, 7809 and 7812 the Vin will be connected to Power source but of course no grounding there. Will this cause a problem ? Thank you.

Latest circuit is better

 

[Rleo6965]

You have to connect ground of all ic regulators. It's safer this way than let it float.

I forgot to place a diode that connect to Vin and Vout. This is to protect the IC regulator. Connect diode in such a way that diode symbol pointing to Vin.

 

[vick5821]

You have to connect ground of all ic regulators. It's safer this way than let it float.

I forgot to place a diode that connect to Vin and Vout. This is to protect the IC regulator. Connect diode in such a way that diode symbol pointing to Vin.

Can you provide me with a diagram ? Mean one diode connected to Vin and one diode connected in the Vout ? So two diode ?

 

[naqionline]

@Rleo6965 : cool sketch !

 

[Rleo6965]

The purpose of diode was discharge path for existing charge voltage on Cout and bypassing IC regulator. Cout Voltage exist if output have no load.