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HELP! project abt DC power supply.


infinity.o3

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Hi everyone!Base on what the teacher had teached,the 78series is for positive volt.For example 7815 is positive 15 volt.Therefore,79 series is for negative volt.For example 7905 is negative 5 volt.So you have to change the voltage regulator.Then i thinking that the Zener diode can be remove since it is to prevent getting inverse voltage.Er...anybody has a better idea?

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heyz manz... i dun tink need zener diode... but i tink muz connect the gnd pin of teh -5V regulator to the 0V wire and the input of teh -5V regulator to the output of the -15V regulator... tat is what i tink lah but i may be wrong... the nthe output of ur -5V regulator is ur -5V output supply lorz... i still dunno where to c0onnect extra capacitors for the -5V regulator... ai yah i not sure lah... n also r the c5 n c6 capacitors electrolytic capacitors too?
WAH SUPER STRESS LIAOZ SOMEONE HELP PLZ

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The function of the diode is to provide only 1 pave for current flow. Since the voltage after a step down from the transformer is AC, the diode is essential to change this AC voltage to DC voltage.

To have a better idea
The graph of the output voltage after step down is actually a sine curve. After passing through the diode, the resultant graph will be a sine curve w/o the negative/positive (depends on direction of diode) part of the curve. So it is necessary to have the present of diode to convert AC voltage to pusalting DC voltage

Aids your research
To get better idea of the concept of a triple output power supply, i suggest that you break up the research into different part.

We noe that a power supply needs
- Transformer to step down AC voltage from the power unit to the required amount
- Retifier to convert AC voltage to pulsating DC voltage
- Filter to convert this pulsating voltage to pure DC voltage
- Voltage regulator to direct the desire output voltage

So it is better that you guyz search through the net to get ideas of these sector. After understanding the function of

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hi, new to here too.
Thanks for the help of the Electronics PRo here.
I'm also from TP and i think that you all should do the explantation on the operation of power supply yourself. It will help you in the further too. Don't just think of copying. Hehe TP students must not violate copyright laws man. (hint: use your EPT book to guide you, its more or less in the book.)

Well, thanks again. Will be back again in the near future. LOL.

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