Question

Resistors Capacitors 5.6k 2, 6.8K2, 8.2k2, 10k12, 12k2, 15k, 18k, 10nF, 15F, 22nF, 33nF, 22k2, 27k 2, 33k 2. 39k12, 47k 2 47nF. 68nF, 100nF, 100uF Inductor 2.7mH In this lab we will be using different configurations of transformer circuits that can be used for converting AC power into DC, effectively making a DC power supply. Each configuration will be plugged into a wall outlet in the lab that will supply AC at 60Hz, 120V RMS. The transformers we have available in lab have a center tap. The circuit schematic of a center-tapped transformer is shown below.

Answer 1

I have simulated the full wave rectifier first and then added the smoothing circuit so that you can see the difference between the two. Also I have used 1N5818 diodes for simulation, diodes from lab are commonly these only or similar to these.

Output of full wave rectifier

17 LTspice XVII - [Draft10.raw] Eile View Plot Settings Simulation Tools Window Help DE TOQQ1037% Draft 10.asc k Draft10.raw 96 3 DVERE Aa.co Viva)-V(vb) 4.06– 3.6V- 3.2V1 2.8V- 2.4v- L 2.0v- 1.64 1.2 - 1 0.8V-A 0.414+ 0.0v Oms 5ms 10ms 15ms 20ms 25ms 30ms 35ms 40ms 45ms 50ms x = 29.57ms y = 2.554V 11 Type here to search o tem e a Ps 9 D A u la 4 ENG 11:05 18-03-2020

As you can see in picture due to non idealities some gap is there between which practical diodes have not yet reached forward bias stage.

Now for smoothening circuit.

Here is the picture of schematic as drawn in LTspice

SINE(O 2.5 60 0 0 0 60) tran 1 R1 D1 5.6k ISR2 Va ciT 100p 5.6k SINE(0-2.5 60 0 0 0 60)

The smoothing circuit is the capacitor in parallel with a resistor.

The capacitor is charged to the peak voltage but can not discharge till the next cycle repeats thus staying near the peak voltage and discharging very low.

Here the values of capaitor and resistance are so selected that,

Rload * C >> 1/2f

where f is frequency i.e 60Hz.

I have used a capacitor of 100u and resistance that i used is 5.6k.

With these i was able to get a peak of 4.6V and ripple frequency of 119Hz with ripple fluctuations between 4.6V and 4.5V so the output fluctuates by 0.1V.

Here is the netlist code of LTspice for your ease,

* C:\Users\hp\Documents\LTspiceXVII\Draft10.asc
D1 Vb N002 1N5818
D2 Vb N001 1N5818
D3 N002 Va 1N5818
D4 N001 Va 1N5818
V1 N001 0 SINE(0 2.5 60 0 0 0 60)
R1 Vb Va 5.6k
V2 N002 0 SINE(0 -2.5 60 0 0 0 60)
C1 Va Vb 100µ
R2 Va Vb 5.6k
.model D D
.lib C:\Users\hp\Documents\LTspiceXVII\lib\cmp\standard.dio
.tran 0 600ms 500ms
.backanno
.end

transient analysis (between 500ms and 600ms)

with Voltage range between 0 and 5V

17 LTspice XVII - [Draft10.raw] Eile View Plot Settings Simulation Tools Window Help DE TOQQ1037% Draft 10.asc Draft 10.raw 96 3 DVERE Aa.co V(va)-V(vb) 5.0012 no 2.50V- 0.00+ Oms 10ms x = 49.32ms y = 3.1000V 1 Type here to search 20ms 30ms 40ms 50m 60ms 70ms 80ms 90ms o te me Pas 9 D ^ ° 1 ENG 12:15 18-03-2020

To see the ripples more clearly

Here you can see how small the ripples are only between 4,5 and 4.6V on the y-axis of the above graph.

17 LTspice XVII - [Draft10.raw] Eile View Plot Settings Simulation Tools Window Help 0 7 O QQA037 % É A SLQ 3 ÝD E E Aa.gr Draft 10.asc Draft10.raw Viva)-V(vb) --------- 4.60V- 4.5917 A 4.58141 4.57V- 4.56V-SH 4.55V- 4.547 4.53V 4.52V- 4.51V- 1 4.50V- 4.49V-| 4.48V+ Oms 10ms 20ms 30ms 40ms 50m 60m 70ms 80ms 90ms x = 74.42ms y = 4.5265V 1 Type here to search o te me Pas 9 D 12:16 Aula 1) ENG 10 16V ENO 18-03-20203