The aim of this investigation is to design, build and test a sensor.
Sensors Coursework Aim and Hypothesis The aim of this investigation is to design, build and test a sensor, which has an appropriate: * Sensitivity * Response time * Resolution * Range * Minimum random/systematic error The sensor I have designed operates by detecting the intensity of light using an LDR (light Dependant Resistor), also known as a photoconductor, in a Potential Divider circuit. In this experiment my input variable will be the mass of milk powder added to 750ml of water. My outcome variable will be the potential difference across the normal resistor (which changes as the resistance varies). I will be measuring this using a multi-meter of resolution 0.01V. This will be positioned as shown in the circuit diagram below. Background A potential divider is a resistor or a chain of resistors connected in series in an electrical circuit. It is used to obtain a known fraction of the total voltage across the whole resistor or chain. When a variable resistor, or potentiometer, is used as a potential divider, the output voltage can be varied continuously by sliding a contact along the resistor. Devices like this are used in electronic equipment to manipulate factors such as volume, tone, and brightness. In this case I have used a potential divider comprising of an LDR and a fixed resistor. I have used two components that have very similar resistances to