Amplification circuit and heat sink used with a light emitting apparatus having varying voltages

摘要

A light emitting apparatus for regulating a current output of an LED at predetermined value with a power source having a wide variety of voltages and chemistries is described. A light emitting diode is electrically coupled to the voltage source. A pulse width modulation controller controls a duty cycle of the voltage applied. A resistor electrically coupled between the voltage source and the light emitting diode is used to regulate output current for the LED. An amplification circuit is electrically coupled to the resistor and the pulse width modulation controller for supplying a feedback voltage to the pulse width modulation controller that is higher than a voltage measured across the resistor.