#
RC Time Calculator

## Capacitor Voltage With Respect To Time

### Vc = V * (1- e^(-t / R*C))

Vc is the capacitor voltage, V is the
supply voltage,

R is the resistance, C is the Capacitance, t is the time,

and e = 2.71828

## RC Time Calculator

** In the drawing at
the left, the time required for the capacitor to charge to 63.2% of the battery
voltage after the switch is closed is the product of the resistance and
capacitance T=(R*C). For example, a 100 uF capacitor and 100K resistor would
require 10 seconds to charge to 7.6 volts using a 12 volt battery. The Java
calculator below can be used to determine the capacitor voltage at other times
after the switch is closed. Any of the five variables can be determined by
supplying the other four. For example, in the graph below, a 1 Farad capacitor
charging through a 1 ohm resistor and 1 volt battery will reach 777 millivolts
in 1.5 seconds. From left to right, the entries would be 1, .001, 1000000, 1500
with the "Instantaneous Voltage" field left blank, or zero. The result would be
0.777. Only one field should be blank or 0 before each calculation. **

GW1NGL NA7KR Kevin Roberts Ham Radio

Page last updated on 09/10/2012 by Kevin Roberts NA7KR a colection of Ham Radio and Electronic Information