Variable DC power supply

[nye]

hey guys, i gotta make this variable DC power supply for a uni project..they hav given us the circuit diagrams and we gotta find out the values of some components. they hav specified an output voltage between Vmin 5V and Vmax 15V, maimum output current of <60mA, output short circuit protection and ripple at Vc1 less than 3% when IL = 50mA(load current)..this means that we hav to calculate C1 and find a suitable value such that the ripple paramters are met...how do i do this?and wht equations/principles do i hav to use??
also, what's a DC power supply with foldback current limiting projection?thanks in advance

 

[blueroomelectronics]

I take it you haven't been attending class.

 

[Valence_4]

I'll give it to you: IC is a LM723.

Diodes D1-D4 must be able to withstand the full load current.

I'll give you a clue: 50mA rectifiers do not exist. In fact, the smallest rectifiers available can withstand a MUCH higher current !

C1 must be able to filter out the ripple to something below a volt. It is quite easy to find the right formula to calculate the right capacitance. For the working voltage take into account Tx's output voltage. Again here, it's VERY easy to find the formula. Give the capacitor a safety margin (e.g. if the working voltage is 9.7 volts, do not use a 10 volt capacitor)

For the remaining components, i gave you a great part of the answer by identifying the IC. Download and read the IC's datasheet. You'll find all your answers there !

 

[nye]

ohhh...no wonder they gav a link to the datasheet in the project outline!!!!

yep..and i havent been attending class..will read up my stuff and do it..thanks heaps guys