Laboratory Materials

Current and resistance in a parallel connection

Principle

In households, electrical devices are often connected in parallel to different sockets of the same electric circuit. The total current and the total resistance of the circuit can be predicted from the partial resistances.

Tasks

Current and resistance in a series connection

Principle

Various components in a circuit can be connected in series. The total resistance and the total current can be calculated from the partial resistances of the components.

Tasks

• Switch an incandescent lamp in se ...

The potentiometer

Principle

Many controls on electrical devices are potentiometers. A potentiometer acts as a voltage divider. It corresponds to a series connection of two variable resistors with a centre tap, whereby the sum of the resistance of the two resistors remains consta ...

Electrical power and work

Principle

A greater number of lamps means more power than a smaller number of lamps. How much voltage and current do you need for the many lamps? Which conclusions on electrical power and work can you drawn from this?

Tasks

...

Charging and discharging a capacitor

Principle

Capacitors are devices that can store charge. Here the details of how the charge gets in and out of the capacitor is looked at.

Tasks

Examine the behaviour of the voltage and current of a capacitor during the charg ...

Diodes as electrical valves

Principle

A diode only allows electric current to pass in one direction and blocks the other one to the current. It therefore acts as an electric valve. This enables alternating current to also be usable to pump charge into a capacitor.

Tasks< ...

Diodes as rectifiers

Principle

A diode only allows current to flow in one direction and blocks the flow of itin the other direction. So the current can flow only during a half wave through a diode in an alternating current circuit.

Tasks

Measure ...

Electrolysis

Principle

The characteristic curve of current against voltage of an electrolytic bath containing copper sulphate solution and having copper electrodes is measured. Visible changes in the electrodes and the bath are observed.

Tasks

The permanent magnet DC motor

Principle

Electric motors for not too high power and simple dynamos are frequently based on the basic principle that an electromagnet rotates in the field of a permanent magnet (or several of them).

Tasks

Examine the behavio ...

The series motor

Principle

The stator field of an electric motor can be generated by an electromagnet, which is then called the excitationwinding. In series motors, the excitation winding is switched in series with the armature winding of the rotor.This type of motor is sometim ...

Bridge rectifiers

Principle

Rectifying circuits with a single diode can only utilize one half wave of alternating current. The bridge rectifier solves this problem by having four diodes connected such that a current path is open for each halfwave.

Tasks

Floating and sinking

Principle

The buoyancy force equals the weight of the displaced liquid: This experiment uses Archimedes' principle to determine to which extent the buoyancy depends on the mass and volume of a body and the density of the liquid.

Cooling by evacuation

Principle

When the air pressure above a watersurface is reduced, the water begins to boil at a certain temperature. The temperature of the water is hereby reduced and further evacuation can finally bring it to 0°C and even lower.

Zero gravity during free fall

Principle

This experiment shows, in a particularly easy manner, that an object in free fall is not subject to acceleration. The state of free fall can, therefore, be used to simulate zero g, as it is experienced in space, e.g. in order to train astronauts prior ...

Frequency of a spring pendulum (on the magnetic board)

Principle

The oscillation of a spring pendulum is recorded by measuring the force. It is hereby shown, that the frequency is independent of the amplitude of the oscillation. Further to this, the spring constant can be determined from the measured values, or a f ...