Description:Illustrated with diagrams. Covers: Electroscope; Galvanometer; Homemade Batteries; Graphite Resistor; Liquid Resistor; Super Capacitor; Thermocouple; Small D.C. Motor Circuits; Inverse Square Law; Light Listener; Monitoring Sunlight; Electromagnetic Probe; Wind Speed Indicator; Rain Sensors; Electronic Thermometer; Motion Detector; Position Detector; Pressure Sensor; Seismometer; earth Movement Sensor; RF Telemetry Transmitter; LED Telemetry Transmitter; Electronic Cricket; Analog Data Logger.