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Lab Power Supply

My old power supply didn't have a current limit and was not protected against short circuit.

This is the second time I change the circuit in this power supply, the previous time I replaced the original circuit by this one:
Oud schema

I changed the circuit to this one because the original burned out after a short on the output terminals.

 

The case:
Labvoeding Front

I wanted to have a higher output voltage then the original, therefore I used a 2*12V 2*5A transformer I had lying around (bought it at a garage sale).

 

The ciruit I'm going to use this time:
Schema Nieuw
Source.

 

The display print covered the entire front off the power supply. Because of that there was no space to put an extra potmeter to regulate the current, so I decided to build new voltage and current meters.

The circuit that I used for that:
Voltmeter schema
For the missing resistor value's see: fig. 1 en fig. 2.
Source.
Datasheet ICL7107.

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Update 27/05/07

The power supply and capacitor pcb's are ready:
Print
Print
Printlayout
Print
Print
Printlayout

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Update 28/05/07

Mounted:

foto print ingebouwd
foto print ingebouwd

 

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Update 06/06/07

I mounted a new heat sink because the old one wasn't big enough.
Koelplaat
Koelplaat

(The bracket is used to press a TO-220 heat sink to the head of the transistor for some extra cooling)

 

The supply for the panel meters had to be isolated from the main power supply, so I build a small pcb with 2 7805 powersupplies.
Voeding display
Voeding display

Mounted:
Voeding Displays
Transfo's voeding displays
voeding

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Update 20/06/07

The panel meter pcb almost finished.

Labvoeding Display
Labvoeding Display
Labvoeding Display

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Update 03/07/07

Today I made the front panel. It is printed on photo paper and glued to the front. The result:
Front

The ZN458A diode's where hard to get. Then I got a tip from Sine, he used the TS431 as a replacement part. I'm receiving those tomorrow, so I can complete this power supply.

This circuit comes in the place of the ZN458A:
ZN458A vervangingschema

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Update 05/07/07

Today I received the zener ic's, and soldered them in. The power supply is now finished.

 

Labvoeding
Labvoeding
Labvoeding
The displays are not as bright as it may appear on the picture.

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