A Portable Electronic Chronometer
G T Baker · Journal of Scientific Instruments · 1948
The timing of small electromagnetic components provides one of the principal problems of light-current engineering. A portable self-contained instrument is described which gives directly the operate or release times of relays and the like, measured to either `make' or `break' contacts. Circuit transients and contact difference times can also be measured. A crystal-controlled pulse source is connected to a gate stage, opened and closed by the apparatus under test. Decade counters are used to indicate the number of pulses which pass in the required time interval. An accuracy of 0.1 msec. can be obtained for periods up to 1 sec., and simple means are disclosed for increasing the range and accuracy.