9B40.10 Lock-in Amp
PURPOSE: To demonstrate the operating properties of a Lock-in Amplifier.
DESCRIPTION: This demo was designed based on the description published in Horowitz and Hill, The Art of Electronics. It is meant to show how a small, clean, signal can be filtered from a large amount of noise. To do this, an LED is powered by the low impedance output of a function generator at 1 hertz. The function generator is also input to the external input of the lock-in amp. A photodetector recieves the weak, noisy signal from the LED. To create a large amount of noise a flashlight is chopped by a fan and the chopped light is input onto the photodetector.
EQUIPMENT:.