9) Electrical Devices

a) AC-Devices

Shows AC current flickering on and off at 60 Hz as the bulb is swung in a circle Uses four AC solenoids to produce eddy currents in a beer can causing it to spin. Shows the effect how the numbers of wire turns effect a step up or step down transformer.
It can also be taken apart to show parts.
Shows Faraday’s law as current is passed through one coil and current is induced in a
second coil. An iron core can be inserted to increase the effect.
A small neon bulb flashes when a battery is disconnected from the inductor
causing the field to collapse
Shows energy stored in a capacitor that pops loudly when discharged. A light bulb and inductor are connected in series. A second light bulb is connected in
parallel to them. When an iron core is inserted in the inductor it changes the inductance and
the bulb in series with it dims, while the bulb in parallel is unchanged.
An Inductor, resistor (red light bulb), and capacitor are connected in series.
As an iron core changes the inductance the circuit is tuned until the light bulb glows.
Shows a trace by audio frequency AC generator or an oscilloscope.
The scope is a standard size 3"x4" screen so it is suited for large classes, but can be seen using the multiledia system.
 
b) DC-Devices Three light bulbs can be connected in series, in parallel, or in combination for students to
see the results.
A very large coil of wires is hand-cranked in the earth’s magnetic field to generate AC and
DC current.
A lecture hall sized example of a motor.
It uses electromagnets instead of permanent magnets.
An example of a simple DC motor using two bar magnets.
This is too small for large classes to easily see. Unless you use the multimedia system.
Example of power generation and transformation of energy. The decay of a capacitor discharging through a resistor that can be displayed by the
Computer.
Shows a plot of voltage Vs current on the screen.
The instructor must slowly change the voltage and press a key to measure the data.
This experiment will take about 10 min to perform and I need 1 hour to get it ready.
Simple take-apart electrolytic cell. c) Meters d) Other The classic Frankenstein high voltage climbing spark High voltage, high frequency coil used to excite gas spectrum tubes. Shows how high voltage, high frequency electricity can be transmitted through air without
using wires.
A fluorescent tube held near the coil will glow nicely.
It also creates dramatic sparks and a lot of noise.
120 Volt AC current runs through a wire made of copper and steel pieces.
The steel glows red hot while the copper remains cold.
Shows the idea of electronic drift in a wire carrying current using a marble bouncing down
A board of atoms (nails) or rolling down a superconductor (No nails in its path). The idea of
Potential gradient can also be discussed based on relating voltage potential to gravitational
Potential.
A light bulb with two electrodes that are inserted in a solution if the solution conducts
Electricity the light will glow.
A high-tech 5 volt 1 farad capacitor that is the size of a half-dollar Classical experiment of floating a charged oil drop in an electric field to find the
fundamental unit of charge.
However this is unsuitable for large classes.