Question

1. Using the circuit shown in Figure 3 (a), choose values for R and C that will produce the waveform shown in Figure 3(b).

IR c = (6) Vol 0-5V - square wave ov 2.5ms Fig.3

Answer 1

As the Vs(t) is 5 V square wave form , resistor divider will reduce the output waveform amplitude. For this not to happen , use

R1=0 OHm

R2 = infinite (practically select 10 M ohm).

So Voltage accros Resistor R2= same as input Vs(t) , that is square wave form of amplitude 5 V.

Now we have and RC circuit with R3 and C. The rise time is 2.5ms

As a thump rule 5RC= 2.5mS.

5 R3*C= 2.5mS

Select R3= 1k ohm

C= 2.5m/(5*1k)= 0.5 u F

So final answer, R1= 0 ohm , R2>> 10 Mohm , R3= 1 kohm, C= 0.5 uF