Applied Sciences

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 ...

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

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

Properties of solar cells - dependence on the illuminance

The current-voltage characteristic of a solar cell

Series and parallel connection of solar cells - open-circuit voltage and short-circuit current

Principle

Series or parallel connection of solar cells can be used to change voltage and current and to adjust them to the consumer's needs. The short-circuit current of solar cells is proportional to the irradiance, while their voltage output is nearly independent of it. ...

Series and parallel connection of solar cells - current-vol-tage characteristics and power ET 5.7

PEM electrolyser and PEM fuel cell

The PEM solar hydrogen model

Principle

Electrical energy from solar cells supplies an electrolyser. The gases generated by the PEM electrolyser - hydrogen and oxygen - are sent directly to the PEM fuel cell. The electrical energy generated is used to drive a small motor. The solar cells can be ...

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.