# ABOUT VOLTAGE

Voltages are always measured between one point in a circuit and another, so to talk about the voltage at a point we need a reference. The reference point is usually one side of the power supply, called GND [1]. It is considered to be at a voltage of 0 volts.
The other side of the power supply is called VCC [2]. The standard supply voltage for all Elbonia Semiconductor circuits is +5 volts.

## Logic Levels

In digital electronics, we only need two voltages, one to represent "1" and the other "0". We call them high and low. High is anything above about 3V and low is anything below about 2V. (Voltages in between are ambiguous and we try to avoid them.)

## Using the Q-Goggles

Your workbench is equipped with a unique Elbonia Semiconductor technology called Q-Goggles (TM) that visualises the voltages present in the circuit using colours. It's activated with the button at the right end of the toolbar.
Try turning on the Q-Goggles and watch how the voltage along the metal strip you created earlier changes as you flip the switch.
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[1] The sound a person makes when he falls face-first in the mud.
[2] Named after Vladimir Charlyev Chernobsky, inventor of the positive battery terminal.