Connect the sensor following the steps in the Getting Started section of the user manual.
Connecting the Energy Sensor to an Energy Source
The Vernier Energy sensor is designed to measure the output of simple generators and solar panels, such as the KidWind renewable energy kits. Connect the red clip lead on the sensor to the positive (red) side of the energy source and the black clip lead to the negative (black) side of the energy source. In the most common configuration, the Load switch should be set to Internal 30 Ω Load.
To use an external load, such as a pump, lights, buzzers, etc., set the Load switch to External Load.
The Check Load LED, , will flash when Go Direct Energy detects that there is a potential between the red and black leads, but no load is connected. If you do not have an external load connected, make sure the Load switch is set to Internal 30 Ω Load. Using Go Direct Energy with this LED flashing will result in measurements of potential, but since no current flows, there will be no other quantities measured.
Go Direct Energy records data in five measurement channels:
- Potential (V)
- Current (mA)
- Power (mW)
- Resistance (Ω)
If your goal is to simply compare the total amount of electrical energy produced in a given time, such as in the KidWind Challenge, the most common number to use is the final value of the Energy column. Energy is the measure of how much total power is generated or used over a period of time. This sensor uses units of joules, abbreviated J, to measure energy.
Current is the measure of the flow of electrons through the wires. When the current is high, the electrons flow quickly through a circuit. When the current is low, the electrons flow more slowly. This sensor uses units of milliamperes, often called milliamps for short. The symbol used to represent milliamps is mA.
To make the electrons move through the wire, they need to be "pushed." The amount of push is called the potential difference. Potential difference is measured in units of volts. The letter V is used to represent a volt.
Power is the measure of how quickly energy is generated or used. This sensor uses units of milliwatts, abbreviated mW, to measure power.
Resistance is a measure of the amount of opposition to the passage of an electric current. The unit for resistance is ohm and is represented by the Greek letter capital omega, Ω.
Using the Load Switch
When the Load switch is set to Internal, the load is an internal 30 Ω resistor inside the Energy sensor. When the Load switch is set to External Load, you will need to connect an external load. For example, in several experiments students explore the effect of load on energy output.