It's a simple RC Series circuit, with voltage being measured across the Capacitor. Input voltage is of pulse type with the following Parameters

• V_on=5V
• V_off=0V
• Pulse Duration=20 ms(On Time)
• Time Period=60ms(Off+On Time)

And RC are as Follows

• R=1M
• C=10u

And how do I calculate the approximate steady state value ~1.67V ?

PS: I could not use the circuitlab simulator as it has only a square pulse input signal