Abstract: Various apparatus and methods of supplying regulated battery power to an electrical device, such as a downhole tool, are provided. In one aspect, a method of providing power to an electrical device is provided that includes providing a plurality of batteries and providing a plurality of controllable regulators for regulating the power output of the plurality of batteries. The plurality of controllable regulators is set so that power is drawn from a minimum number of the plurality of batteries necessary to satisfy demand from the electrical device. The electrical device is enabled to periodically draw power from and thereby depassivate each of the plurality of batteries.

Abstract: Various apparatus and methods of supplying regulated battery power to an electrical device, such as a downhole tool, are provided. In one aspect, a method of providing power to an electrical device is provided that includes providing a plurality of batteries and providing a plurality of controllable regulators for regulating the power output of the plurality of batteries. The plurality of controllable regulators is set so that power is drawn from a minimum number of the plurality of batteries necessary to satisfy demand from the electrical device. The electrical device is enabled to periodically draw power from and thereby depassivate each of the plurality of batteries.

Abstract: One aspect of the invention is a system controlling individual access at an airport. The system comprising an access card having machine readable information of an encoded biometric characteristic. An access control terminal includes a reader for reading the encoded biometric characteristic from the access card. A biometric reader makes a contemporaneous biometric reading of the presenting individual. A processor grants or denies access by comparing the read encoded biometric reading with the presenting individual biometric reading. Another aspect of the invention is controlling entry to commercial vehicles. A biometric reading of a passenger is taken. A boarding pass having the passenger's biometric reading is generated. A contemporaneous biometric reading of each passenger presenting a boarding pass is taken. The presented boarding pass encoded information is compared to a contemporaneous input. Based on the comparison, access is granted or denied.

Abstract: A signal amplifier system for use in a downhole logging system wherein a signal transmitter is mounted in a sonde suspended on a logging cable thousands of feet into a borehole. Variable slew rate amplifiers connected to a differential amplifier are set forth. Preferably, programmable amplifiers having a gain determined by a driving current are used. Two such amplifiers are connected to the input signal, and they are driven by different current sources. The output signals are summed at a differential amplifier. Through the use of different slew rates, the incoming signal is amplified by the two programmable amplifiers and the outputs of the two amplifiers are then subtracted from one another. Signals which pass equally through both programmable amplifiers (due to slew rates which do not cause limiting) thus are subtracted from each other.

Abstract: For use with a down hole logging system equipped with a logging cable having two wires therein, the preferred and illustrated embodiment sets forth a system which conducts electrical power and telemetry signals along a two wire logging cable. AC power is generated at the surface for transmission to a power consuming load in the sonde. This AC supply has a specified frequency, there also being data gathering equipment in the sonde which forms an AC telemetry signal transmitted up the two wire logging cable. This disclosure is directed to an improvement in the telemetry drive circuitry which maintains the isolation between power flow and signal flow. The circuitry incorporates FET output transistors, transformer coupled, to provide the necessary output signal and isolation.