Team 2 Solar Kiosk Project Sponsored by: Team Members: Jakub Mazur - Manager Eric Tarkleson – Presentation/Lab Josh Wong - Webmaster Ben Kershner – Document Preparation

Current Sensing Applications Pros Cons The Hall Effect Shunt Resistors Making your Data useful Questions

Applications Measuring Power Consumption Design for Safety – GFCIs, fuses, circuit breakers Temperature optimization – High current = hotter components

Shunt Resistors vs Hall Effect

Shunt Resistor Low failure probability Cheap Wastes power Not suitable for all currents Limited sensing range Requires additional voltage measurements Hall Effect Sensor Isolated from current source Higher precision Passive device More expensive Can be integrated into an IC device

The Hall Effect When there is a Magnetic field in the presence of a conductor a voltage is induced due to electron and hole drift Electron – negative charge carrier Hole – positive charge carrier

Hall Effect VHVH L W t + I B E Hp E Hn + + +

The Hall Effect - Math Vhall = -(I*B)/(d*n*e) Rhall = -1/(n*e) current through wire Bfield = Uo*Ip/(2*pi*r) I= current B = Mag Flux Dens d = depth of plate e = electric charge j = current density n = charge carrier dens r = distance to center of wire Uo = 4*pi*10^-7

So what? We can use this to our advantage We can detect – B field – Current – Voltage – Charge drift velocity We can do this without having inline components (like a shunt resistor)