Based on STC89C51RC SCM, through low-frequency multiplier technology will move to high frequency, and then counting method for measuring frequency, and a measurement range of 0.01HZ ~ 1MHZ, accuracy of 1 / 100 of measuring frequency. The frequency of only a few external resistance of containers and work the clock for the microcontroller crystal oscillator circuit, we can achieve frequency measurements, the hardware is simple, small size, easy to implement characteristics. Can directly drive LCD display frequency. The whole circuit by 5 V DC power supply, low power consumption, facilitate the production of portable measurement equipment.
