RC timing circuit application
If that &quot;timing interval&quot; places a fixed voltage across the charging R+C circuit, with the R in series to set current by { (Vin - Vcapacitor) / Rvalue }, then the capacitor voltage rises rapidly at first (the slewrate is exactly {Vin/ (R * C)} ) but the charging rate exponentially becomes slower as the Vcapacitor gets closer and closer to the final value.