Abstract: An ultrasonic energy detector advantageously supplies both frequency and amplitude information which is related to the ultrasonic frequency and the amplitude of the detected ultrasonic energy. Frequency division is employed to reduce the relatively broad range of ultrasonic frequencies into a narrower audio frequency range while still providing information useful to identify the ultrasonic energy by frequency detection. The effect of anticipated background noise at all levels of gain selected is eliminated by subtracting a signal representative of the anticipated background noise and proportional to the selected predetermined gain from the amplitude of the detected ultrasonic energy.

Abstract: A conductor tracer which is used to trace and identify an energized conductor includes a transmitter which draws a current tracing signal from the energized conductor. The magnitude of the current drawn is regulated substantially independently of the voltage on the conductor. A current regulating circuit is periodically switched to conduct current from the energized conductor. The constant current circuit responds both to the current drawn and the voltage on the conductor. At relatively high voltages the current is conducted primarily through passive resistive elements which can absorb the relatively high power and dissipate it as heat. At relatively low voltages, a current regulating transistor regulates the amount of current drawn. At relatively low voltages on the conductor the regulating transistor does not experience damaging heat.

Abstract: A conductor tracer which is used to trace and identify a conductor energized by an AC energizing signal includes an improved transmitter by which to draw a current tracing signal from the energized conductor. The current tracing signal is phase shifted by 180.degree. upon the occurrence of each subsequent half cycle of the AC energizing signal. By phase shifting the current tracing signal when the direction of current flow in the conductor reverses due to the change in polarity of the AC energizing signal, the net effect is that a uniform phase or polarity magnetic field tracing signal about the conductor is maintained. The uniform phase or polarity magnetic field tracing signal makes detection of the conductor more reliable and easily accomplished.

Abstract: A conductor tracer apparatus includes a tracer signal generator and a detector for detecting electromagnetic and electrostatic fields created by the tracer signal in the conductor. Two electromagnetic transducers in the detector obtain an omnidirectional flux reception pattern. The separate signals from the two electromagnetic transducers are both added and compared, and the comparison obtains a directionality relationship which controls the magnitude of a display indication related to the summed signal representative of the omnidirectional flux reception. An electrostatic transducer is also provided in the detector. The signal from the electrostatic transducer is added to the signals from the electromagnetic transducers to obtain reliable conductor detection even when one of the electromagnetic or electrostatic fields is adversely influenced.

Abstract: Tracing, identifying and distinguishing electrical conductors in a power distribution network energized by a varying or alternating voltage is achieved by use of a transmitter (10) which absorbs or conducts pulses of current in the power distribution network, and by a remotely located receiver (12) which detects the electromagnetic field signals corresponding to the current pulses conducted through the network conductor. The transmitter includes means (10", 400) for varying the time width duration of each pulse of current conducted in relation to the instantaneous voltage present on the conductor during the pulse, in order to deliver pulses which are of substantially uniform and constant energy content. Discrimination of adjacent electrical conductors is enhanced because the strength of the electromagnetic field signal remains substantially constant despite the alternating or varying nature of the voltage on the distribution network.

Abstract: The Miller effect capacitance of an amplifying device, such as a transistor, is effectively used to increase the gain and/or the high-frequency cut-off point in the band width of a relatively high-frequency amplifier. The transistor or equivalent amplifying device is connected in an emitter follower configuration and the amplifier output signal is derived therefrom. An input signal to the amplifier is applied through an input transformer. The secondary winding of the input transformer is electrically connected to the base of the transistor. The emitter follower configuration of the transistor causes the Miller effect capacitance to be effective in a resonant circuit which includes the effective inductance of the secondary winding of the input transformer and the Miller effect capacitance.

Abstract: Tracing and identifying electrical conductors in a power distribution network is achieved by use of a transmitter operating on a duty cycle of delivering or absorbing current pulses at a predetermined frequency from the power distribution network, and by use of a remotely located receiver which detects the electromagnetic field signals resulting from the current pulses in a predetermined cyclic manner of operation defined by a sample period and a reset period. During the sample period the receiver supplies an indication of the maximum received strength of the transmitter signal. The relationship of the duty cycle of the transmitter and the sampling and reset periods of the receiver reduce the potentially adverse influences of spurious signals on the receiver. The transmitter may include means for delivering constant energy content pulses to the power distribution network, thereby rendering the signals detected by the receiver insensitive to variations in voltage on the power distribution network.