Abstract: A digital indicator (1) includes: a main body (10); a spindle (11) being axially slidable and having a contact portion (12) on one end, the contact portion abutting a to-be-measured portion; a detector (13) that detects an absolute displacement amount of the spindle (11) relative to the main body (10); and a display (14) that digitally displays the displacement amount of the spindle (11) relative to the main body (10) detected by the detector 13. The spindle (11) is slidable in a direction away from the contact portion (12) beyond the detectable range of the detector (13).

Abstract: A digital indicator (1) includes: a main body (10); a spindle (11) being axially slidable and having a contact portion (12) on one end, the contact portion abutting a to-be-measured portion; a detector (13) that detects an absolute displacement amount of the spindle (11) relative to the main body (10); and a display (14) that digitally displays the displacement amount of the spindle (11) relative to the main body (10) detected by the detector 13. The spindle (11) is slidable in a direction away from the contact portion (12) beyond the detectable range of the detector (13).

Abstract: An ultrasonic measuring apparatus comprising a master unit and a slave unit each having a respective transmitter circuit for transmitting towards the other unit a burst of ultrasound and each having a respective receiver circuit to detect the burst of ultrasound transmitted by the other unit. The slave unit is responsive to the detection of a burst transmitted by the master unit to transmit a return burst back to the master unit. The master unit includes control means for disabling its receiver circuit during transmission of the said burst to the slave unit and thereafter until the end of a first period of time which is sufficiently long to permit all echoes from the said burst to decay to a level where the master unit receiver circuit is not sensitive enough to detect them.