What Resistance Value is Needed for a Pacemaker Operating at 60 BPM?

[bigborat]

Homework Statement

A heart pacemaker is designed to operate at 60 beats/min using a 4.0uF capacitor. What value of resistance should be used if the pacemaker is to fire when the voltage reaches 63 percent of maximum?

Homework Equations

The Attempt at a Solution

0.63 x (4/1000) x 60
I don't know if this method is right though?

 

[Delphi51]

The 63% is not a random choice; it is the standard for the "time constant" idea. You can look it up in Wikipedia if it isn't handy in your textbook. http://en.wikipedia.org/wiki/Time_constant, fifth paragraph.

So, you need a formula for the time constant of a capacitor to solve this problem.