Abstract: A handheld dual voltage circuit tester, method and electronic circuit that quickly allows a technician to determine whether an automotive electrical system runs on a 12-14 volt circuit or 36-42 volt circuit. The tester may be used for automobiles having a single voltage electrical system, or automobiles with distinct electrical systems operating on one of a 12-14 volts circuit or a 36-42 volt circuit. The tester includes a screwdriver-type elongated handle and probe tip. The tester also includes electronic circuitry disposed within its handle, heat shrink tubing, a conductive spring assembly, a strain relief, a retractable coil cord, a ground clip and insulation that encloses the ground clip. The tester also includes electronic circuitry that emits light of a first color when a 12-14 volt circuit is sensed, and light of a second color when a 36-42 volt circuit is sensed.

Abstract: A handheld dual voltage circuit tester, method and electronic circuit that quickly allows a technician to determine whether an automotive electrical system runs on a 12-14 volt circuit or 36-42 volt circuit. The tester may be used for automobiles having a single voltage electrical system, or automobiles with distinct electrical systems operating on one of a 12-14 volts circuit or a 36-42 volt circuit. The tester includes a screwdriver-type elongated handle and probe tip. The tester also includes electronic circuitry disposed within its handle, heat shrink tubing, a conductive spring assembly, a strain relief, a retractable coil cord, a ground clip and insulation that encloses the ground clip. The tester also includes electronic circuitry that emits light of a first color when a 12-14 volt circuit is sensed, and light of a second color when a 36-42 volt circuit is sensed.

Abstract: A method for forming a doped optical fiber includes drawing the optical fiber from a doped glass supply at a draw speed and a draw tension sufficient to introduce a heat aging defect in the optical fiber. The optical fiber is treated by maintaining the optical fiber within a treatment temperature range for a treatment time while preferably maintaining the optical fiber within a treatment tension range to reduce the tendency of the optical fiber to increase in attenuation over time following formation of the optical fiber. Apparatus are also provided.

Abstract: An evaporative emission tester is used to evaluate the integrity of a vehicle's evaporative emission control system, including determining the system's purge capability. The emission tester performs a purge flow test to determine whether fuel vapor stored in the vehicle's evaporative canister and present in the fuel tank is being drawn into the engine for combustion at a minimum amount. The emission tester also performs a pressure test of the vehicle's evaporative canister purge system, which includes the fuel tank and lines. The emission tester can function as a stand-alone unit or as an integrated product with a host computer.

Abstract: An evaporative emission tester is used to evaluate the integrity of a vehicle's evaporative emission control system, including determining the system's purge capability. The emission tester performs a purge flow test to determine whether fuel vapor stored in the vehicle's evaporative canister and present in the fuel tank is being drawn into the engine for combustion at a minimum amount. The emission tester also performs a pressure test of the vehicle's evaporative canister purge system, which includes the fuel tank and lines. The emission tester can function as a stand-alone unit or as an integrated product with a host computer.

Abstract: A hand-held contact tachometer includes an elongated hollow handle comprising two interconnected members defining a clevis at one end thereof and carrying therewithin a magnetic sensor disposed adjacent to the clevis and conditioning circuitry coupled to the output of the sensor. The clevis has hub portions defining an axle on which is rotatably mounted a contact wheel of molded construction including a body of non-magnetic material in which is embedded a toothed magnetic wheel and a bearing. The wheel is provided with a frictional ribbed surface on its outer periphery to facilitate engagement with an associated moving surface, thereby rotating the wheel to generate a pulsating signal having a frequency proportional to the speed of the moving surface.

Abstract: The modular electronic device includes a main unit and at least one plug-in module adapted to be removably slid on to and mounted on the main unit. There are first and second interfitting connectors respectively on the main unit and the module which automatically interfit when the module is mounted. First and second interfitting track structure are respectively on the module and main unit to facilitate sliding the module onto the main unit. Finally, there is first and second interfitting latching elements respectively on the main unit and the module to hold the module latched in place.

Abstract: A sensor is periodically energized and the sensor output is amplified, the amplified signal being applied to two sample-and-hold circuits which are alternately activated in response to the sensor drive, one being activated only when the sensor is energized and the other being activated when the sensor is not energized. One of the samples is subtracted from the other in a summer for cancelling the amplifier offset. The summer output may be buffered, and there is also applied to the summer an offset correction signal for cancelling sensor offset and buffer offset inaccuracies.