Question

Your supervisor has also passed on to you a power supply circuit sketch to upgrade your last power supply (Assignment 1) so that it has a Fixed 5V regulator output and a Variable Voltage Regulator output. . Analyse the variable regulator section (containing the LM317 IC) and determine the expected output voltage range the circuit should achieve by the range of adjustment of the 1k potentiometer. Build the circuit and verify the voltage range available. Ensure it can achieve 12V within its range. Tabulate the expected and measured ranges. Half-Wave Rectification CIRCUIT 1 D1 1N4004 T1 Vo C1 240Vac,非12Vac R1 1k (25V) CIRCUIT 2 Full-Wave Rectification D2 2W10 T2 4 x 1N4004 C2 Vo R2 25 CIRCUIT 3 Rectifier with Zener Regulator D3 2W10 тз 4 x 1N4004 0 V1 240Vac12Vac C3 R3 2k7 Vo (25V) ZD1 5V1 0.5W Red LED LED1

Answer 1

• 
  12 V 1SO S2. 2.+k PoT 680 $2
  for fixed 5V regulated voltage can be achieved using 7805.
• variable output voltage range is 6-12 V which is achieved using LM317.
• variable Output voltage is given by,
  • Vout =1.25 (1+((R2+680)/R1))
• Vout is depends on R2 which varies upto 1K.

R2	Vout =1.25 (1+((R2+680)/R1))
1000	12.91666667
900	12.22222222
800	11.52777778
700	10.83333333
600	10.13888889
500	9.444444444
400	8.75
300	8.055555556
200	7.361111111
100	6.666666667
50	6.319444444