It measures electrical noise in the order of 10 -8 volts. To construct this device I had to use metal film resistors, cylindrical metal capacitors, LM741 amplifier, and 2N3904 transistor. We bought a LM721 amplifier to use in our circuit, but when it arrived we found that it was too physically to small for our circuit. We will have to integrate it into the circuit at a later date. Below are the details of the project.
Every electrical circuit has some type of noise in it.
This noise becomes undesirable when the signal to noise ratio becomes low enough to adversely effect the operation of the electrical circuit. Electrical devices that cause changes in voltage or current are common sources of noise. Noise is often described by how it is coupled in a circuit. The five basic types of couplings are capacitive, inductive, radio frequency, common impedance, and conducted. Of these five the ones that affect the project are capacitive, inductive, and conducted.