Abstract: A ground pick-up tachometer for detecting a rotational speed of an engine in a vehicle includes a probe arranged for connection to a vehicular ground to detect signals emitted from an ignition system of the engine. A tachometer circuit is operatively connected to the probe to identify the detected signals representing ignition sparks and provide an output representative of the rotational speed of the engine based on the identified signals. The tachometer circuit includes a circuit common reference, separate from the vehicular ground.

Abstract: An apparatus for testing an internal combustion engine is disclosed. The apparatus comprises a probe for electrical connection to at least one spark plug wire of the engine being tested. A peak hold circuit operates to store a representation of a peak firing voltage of the rectified secondary ignition signal and attenuates the stored representation at a predetermined rate over time to enable measurement of peak firing voltage. The testing apparatus is connected to a voltmeter to display a value of the peak firing voltage. Alternatively, the testing apparatus includes a display for displaying the value of the peak firing voltage. Preferably, the testing apparatus is housed in a housing of a size to be held in a user's hand, with a power supply contained therein.

Abstract: A battery package having a casing which contains at least one electrochemical cell electrically connected to a DC to DC converter. A pair of electrical connections are located on the casing to electrically connect the battery package to a load. The converter conducts and the cell discharges only when a load is present across the electrical connection.