Abstract: A moisture sensing device for an irrigation system is disclosed. A pair of concentrically disposed cylindrical conductors are separated by a fibrous material, such that a capacitor is formed whose resistance will vary in response to the level of moisture present in the fibrous material. An electrical circuit is connected across the cylindrical conductors for measuring the variable resistance caused by the level of moisture present in the fibrous material. If the soil is dry enough to require watering, the sensor circuit will produce an output signal to the appropriate solenoid in the irrigation system to permit watering.

Abstract: An induction heater is provided for heating electrically conducting workpieces. The heater comprises an induction coil having a number of turns including long straight conductors wherein a major portion of the long straight conductors are secured to a concrete support beam. The conductors and the support beam vibrate together in response to electromagnetic field forces generated during operation of the heater. The coil is caused to vibrate with the coil support beam by a hard adhesive which bonds the support beam and the coil or by tension members which hold the coil tightly to the support beam.