Wilson Greatbatch had been working on on ways of sensing the rate of heartbeat by using electrical circuits. He inserted the last component in his oscillator circuit expecting a sound like a middle "C" on the piano. To his surprise, the oscillator made a "click-click-click" sound at a rate of about 1 beat per second--about 1000 times slower than the tone he expected!
As an electrical engineer, he was experienced with the various ways in which electricity could be controlled using transistors, capacitors, inductors, and resistors. The circuit he was now working on required one last resistor--one that had a color code of Brown, Black, Orange--signifying 10,000 ohms (a measure of resistance). He reached into his supply drawer and pulled out what he thought was the right resistor. Instead, he placed one with a color code of Brown, Black, Green--1,000,000 ohms or 1000 times more resistance than the required part.
Listening to the clicking sound, Wilson had a brainstorm. The sound reminded him of a heartbeat. Each click was like the "lub-dub" rhythm of the heart. He wondered what would happen if he could connect the output of his new electrical circuit to a heart. The idea for the pacemaker was born.
A pacemaker is a device that simulates the electrical signal the heart muscle receives to contract. This electrical signal from the brain can be interrupted or slowed causing significant health problems to the person. Pacemakers are effective because they can keep the heart in a regular rhythm and can be adjusted to conform with each person's body system.
For Greatbatch the hard part of making his idea a reality was ahead. How could he make the circuit fit inside a small package? How could the components be protected from body fluids? How could a battery be made small enough and long lasting enough so that replacement batteries were needed only at long intervals? And finally, how could he get this all worked-out fast enough to get the patent first? These were answers that Greatbatch sought. He worked for two years to refine his device and his was the first implantable pacemaker. He received patents for the circuit, encasing, and thereafter batteries used to fuel the devices. His original patent can be seen at here. In 1985, his pacemaker was recognized as one of the ten greatest engineering achievements of the last 50 years by the National Society of Professional Engineers.