Abstract: A battery booster apparatus includes a portable support structure on which are mounted a battery, jumper cables for connecting the battery in parallel with an external battery that is in a low charge condition, an AC-powered charger for charging the battery, and a solar panel for charging the battery when the charger is not powered. The apparatus may include components for switching between the charger and the solar panel so that the solar panel is connected to the battery when the charger is not powered and disconnected when the charger is powered. The switching components may operate automatically and include a relay electrically connected to the charger so that the relay operates when the charger is powered.

Abstract: In a switchable impedance tester for measuring very small impedances, the effect of switch impedances is eliminated by connecting the test load between two switching transistors in their emitter-collector circuit, and driving them with operational amplifiers arranged to urge their inputs into equality. A test voltage source is connected across first inputs of the amplifiers, and the other inputs are connected between the respective transistors and the load. This produces an operational condition in which the voltage across the load is independent of the parameters of the switching transistors, i.e. the switching transistors appear to have zero impedance.