- Power supply: 9V battery (not included)
- Dimensions: 50 x 50 x 22 mm / 1.9 x 1.9 x 0.9 inches
The MadLab Electronic Kit: Lie Detector works by measuring galvanic response. In other words, when a person lies, they tend to sweat. Perspiration has a high sodium content, which makes sweat conductive. Dry skin has a resistance of approximately one million ohms, while moist skin has a resistance that is reduced by a factor of ten or more.
When a person holds the probe wires, it changes the voltage at the upper probe wire depending on their skin resistance. The skin resistance is in parallel with R2 and, due to its similarity or lower value compared to R2, the voltage at the probe wire decreases as skin resistance decreases.
