-2 x 1N4007 diodes
-1 x 2v2 zener diode
-1 x LM317 regulator
-180ohm carbon film resistor
-265ohm " "
-820ohm " "
-2 x 25v 330uF capacitors
Calculations:
Resistors R3 & R2
Vout=Vref ( 1+R3/R2)
5v/1.25 = (1+R3/R2)
4= (1+R3/R2)
-1+4=1+R3/R2-1
3=R3/R2
R2x3=R3/R2xR2
3R2=R3
3x240=720
R2=240ohms R3=720
the calculation above is a ratio 3:1 (240:720)
Note# as the 240 and 720 not available i had to grab the closest ones above them (265ohm and a 820ohm and this is still the 3:1 ratio so it will not effect the opperetion of the circuit)
How the circuit works:
As the Raw 12v supply goes through the circuit it is being regulated by the zener diode which anything above the zener voltage is passed on to ground. When it passes through the regulator the out put voltage should be 5v because of the 3:1 ratio of R2 and R3. The capacitors job is to prevent voltage spikes by allowing any high voltage to pass through them to ground. The LED is there to indicate that the circuit is working, it does by lighting up when the 5v out put is coming out of the regulator.
Test procedure:
to test if 5v is coming out of the regulator i did an availible voltage test at the 5v output and i got 5v which means the circuit is regulating the raw 12v supply into a 5v output.
Problems:
One problem i had was at first when i completed the circuit the output voltage was 9 volts not 5 which indicated something wasnt working. Just by doing a visual check i noticed one of the 1N4007 diodes was around the wrong way, i De-soldered and re soldered it back in the right way and got an output voltage of 5v
Reflection:
things i could of done better:
-dont stretch the legs of some of the components so far to make the circuit look better.
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