Decade Counting Circuits

A direct-coupled pentode trigger pair, previously described, is made the basis of two simple ring-of-ten circuits for high speed counting. One of the circuits is especially suited for the counting of sharp pulses up to a frequency of 105 cycles per second. The other circuit is especially suited for frequency measurements on periodic currents of arbitrary wave form and of frequency from zero to above 105 cycles per second. The number of pulses or cycles counted by one ring-of-ten is indicated on the screen of a cathode-ray oscilloscope tube. Several of these ring-of-ten units, each with its cathode-ray tube, can be connected in cascade to make electronic counting with direct indication of the decimal figures possible.