frequency counter

In its basic form the instrument is a sixdigit frequency/period meter. The basic counter/latch/display is shown in figure 1, which is the circuit of two stages of the counter, showing how the 7490`s are cascaded, and how the interconnections between the latch and reset inputs are made. The segment series resistors are shown dotted, as the circuit may be used with either Minitron or LED displays, and series resistors are not required with Minitrons.