The invention is based on a measuring instrument.  A sensor is made known in DE 29 23 644 C2 that comprises a cylindrical frame produced out of ferromagnetic material.  A permanent magnet is cylindrical frame produced out of ferromagnetic material.  A permanent magnet is moved in sliding fashion in the frame, the movement of which is proportional to the movement of a component.  Moreover, a magnetosensitive element is arranged in a gap of the frame and, therefore, in the closed magnetic circuit created by the magnet, the output signal of which magnetosensitive element is proportional to the movement of the magnet.  Since the magnet slides directly on the inside of the frame, however, high frictional losses can occur that corrupt the output signal.  Since the housing is closed, a varying magnetic flux is produced. 
In contrast the measuring instrument according to the invention has the advantage that the magnet-since it is attached to a sledxe2x80x94can execute a sliding movement with relatively low frictional losses.  The sled can be designed to be relatively slideable by way of its construction as well as by way of the materials used.  Moreover, the sled can be incorporated in the closed magnetic circuit of the magnet in a simple fashion.  Due to the conical seating of the sled, the magnet can be inserted and moved without play.  The air gap is not affected by the force of the magnet, but rather kept constant during the measuring motion.  Fluctuations in the output signal are thereby avoided.  The guidance of the support and the attractive forces of the magnet are decoupled.  No offset voltage is required with this measuring instrument.  The measuring instrument can be easily integrated in systems to be measured, or it can be used as an independent sensor.  It is therefore feasible that it can be used in transmission controls, or for measuring pedal travel or valve lift, for example. 
Advantageous further developments and improvements of the measuring instrument indicated in Claim 1 are possible as a result of the measures described in the subclaims.