# RC Circuit Analysis - Finding Capacitance

I'm lost on how to approach the following problem (apologies as I'm not an EE).

In the following circuit, I'm trying to find the capacitance that will limit the node voltage (where the voltmeter is attached right above resistor R2) to below 4 volts for 15 milliseconds.

Can someone provide some guidance on how to approach this??

• What do you know about capacitors? Do you know the t=RC rule? Do you also know V=IR? – Puffafish Jul 17 '19 at 8:18

$$I(R2)=\frac{V}{R1+R2}(1-e^{-\frac{(\frac{R1}{R2}+1)t}{R1C}})$$