A power source test instrument for a circuit includes a voltage test circuit and a current test circuit. Two operational amplifiers form the voltage test circuit and the current test circuit. The power source test instrument is convenient and saves time when conducing various kinds of tests including: charging, discharging, dummy battery loading, and current testing. Additionally the power source test instrument ensures a full test without damaging or requiring disassembly of the product under test.

An apparatus and method for determining the status of a stand-alone power source, which includes a communications port that attaches to the power source, a processor linked to the communications port to process the data and output device to view the data. Additionally, a charger can be incorporated as a dual function to better diagnosis the power source as well as a means for charging the power source.

A combination battery, light bulb, fuse tester having novel features. In particular, the tester includes a novel probe apparatus including an actuator, a pair of opposed probe arms, each of the probe arms having an electrical contact on an end thereof, the probe arms being adapted such that operation of the actuator biases the ends of the probe arms away from each other to an open position allowing the electrical poles of a battery, light bulb, or fuse to be tested to be contacted by the contacts on the probe arms. Additional features include magnetic probe contacts to facilitate the testing of a battery, light bulb, or fuse.

An arrangement for generating and storing metering information in a meter for measuring a consumed commodity includes a processing circuit and a non-volatile, rewriteable random access memory. The processing circuit is operable to generate metering information. The non-volatile, rewriteable random access memory stores metering information during normal operation, and is operable to retain the stored metering information in the absence of external electrical power.

Children's ride-on vehicles having charge indicator assemblies that are adapted to provide at least a visual indication of the state of charge of the ride-on's battery assembly. The vehicles are reduced-scale vehicles, often formed substantially from molded plastic, that are sized for use by children and which include battery-powered motor assemblies. The vehicles include a charge indicator assembly that is adapted to selectively assess an input voltage from the battery assembly and provide an output representative of the relative state of charge of the battery assembly. In some embodiments, the charge indicator assembly includes a charge indicator module that is mounted on the vehicle's body, optionally in a position to be accessed by a child operating the ride-on, and which includes a button or other actuator adapted to cause the charge indicator assembly to assess the state of charge of the battery assembly.