Abstract: The zero position in a sine cosine indicator for a tachometer is determined by a projection on the magnetized rotor arranged to encounter a stop projecting from the enclosing bobbin wall. A weak stationary secondary magnet is located adjacent the rotor with the magnetic axis of the secondary magnet rotated through an angle less than full scale from the magnetic axis of the rotor when the rotor is in the zero position. Alignment and crossover between the two magnetic axes is arranged to occur when the pointer associated with the rotor is approximately at midscale. Consequently any distortion of the scale to either side of the crossover point is in opposite directions and the overall appearance of the scale to the casual observer is linear.

Abstract: The invention contemplates a moving-magnet meter movement wherein frame structure to pivotally support the moving element also includes coil-supporting bobbin structure, so that a fixedly mounted coil can be wound directly on the frame structure after assembly of all moving parts including the needle pointer of the moving element. The frame structure is also so arranged in laterally offset relation to the bobbin region that terminals with separate terminal-strip elements can project laterally further from the bobbin region and outward of the frame structure, whereby coil lead and/or other circuit-element connections within the meter can be made in laterally projecting regions of the terminal-strip elements, thus enabling a single dip-soldering operation to consolidate all electrical connections. Other features are described.

Abstract: The invention contemplates tachometer apparatus which functions from an electric pulse input which is of frequency directly related to engine speed of an internal combustion engine. In application to a modern automobile assembly line wherein successively assembled vehicles may have various-sized engines in random succession, the particular feature of the invention is that with essentially the same rectifier circuit and associated indicating meter, and with the simplest of manipulation or connection of a single element, the meter can be direct-reading and fully calibrated whether the invention is applied to a four-cylinder engine, to an eight-cylinder engine or to a six-cylinder engine.