Abstract: An electromagnetic noise source locator is comprised of an audio amplifier which is connected to drive a speaker and to which is connected at the input a series circuit that includes a very small antenna loop of area less than 1 in.sup.2, a diode and a capacitor. This apparatus responds only to bursts of radiated energy and furthermore responds only to such bursts having frequency components over about 1 GHz. It is therefore particularly suitable for the selective sensing and location of sparking gaps as may occur on power lines.

Abstract: A resilient insulative layer of a plastic foam material is sandwiched between a dimpled carbon powder loaded plastic sheet and a resilient carbon powder loaded plastic foam pad. The dimples extend part way through holes provided therefor in the insulative layer. This sandwich assembly being placed under a bed mattress serves as a mattress-switch indicating electrically by contact between the sheet and the pad the presence of an occupant in the bed or his absence by lack of such contact. The characteristic time of the pad material for returning to its original shape is substantially longer than the corresponding return time of the insulative layer. Reliable operation is obtained for a wide range of occupant weights regardless of the weight(s) of the previous occupants.

Abstract: A radiation locator apparatus includes a tuned or tunable radio receiver having an automatic gain control (AGC) circuit that provides a d.c. signal having an amplitude that is a function of the strength of the received radiation. A free running voltage controlled oscillator (VCO) is connected to earphones and produces a sound pitch that varies as a function of the magnitude of the d.c. (AGC) signal. An increase in the sound pitch may indicate an increase in the strength of the radiation received. When the locator is transported in a direction toward the source of radiation, the pitch increases thus guiding the operator to the source. The range of audible pitch may be extended by employing a pulse generator type of VCO since pulse repetition rates less than ten pulses per second are audible as spaced clicks that are equivalent to an extra low range of pitch.