1. The problem statement, all variables and given/known data Hi there. I have a simple RC circuit with a battery voltage of 10 V, R = 1 Ω, C = 1 F and a switch. I want to use the Explicit Euler (forward divided difference) to solve the equation and check for stability, rather than using a ODE. I am finding the equation for when the capacitor is fully charged and then the battery removed, standard situation etc. 2. Relevant equations C. dv/dt + V(t)/R = 0 (loop equation for the circuit) 3. The attempt at a solution The first thing I attempted to do was rewrite / rearrange the circuit in the form v(tnew) = v(told)(1 + a.Δt)n then check what value of t the equation would be unstable for. dv/dt + V(t)/RC = 0 Rewriting dv/dt as (Vf - Vi)/Δt, (Vf - Vi)/t + V(t)/RC = 0 ... leads to Vf = Vi - Δt/RC Vf = Vi(1 - Δt/RC) ----- equation 1 So a = -1/RC = -1, giving v(t) = Vi(1 - Δt) v(t) = 10(1 - Δt) For v(t) to be unstable, |1 - Δt| > 1 ∴ t should be 2sec or more. However, logically speaking shouldn't the equation be unstable at values of t > 1 sec. Because if you plug Δt = 1 sec, the final voltage is always 0. Where have I made a mistake?