Take a Q3 of 74 16 1 as the carry output of this stage, which is an octal counter. The four outputs (Q3, Q2, Q 1, Q0) of the first stage are 8, 4, 2, 1. The counting input of the first stage is input from the CLK terminal, and the CLK of the second stage is connected to Q3 of the first stage, which constitutes the second stage of the octal counter. By analogy, a multi-bit octal counter circuit is formed.

The synchronous addition counter 74LS 16 1 (or 74LS 160) and the 24-input NAND gate 74LS20 try to form an arbitrary decimal counter, and display the counting decimal with LED digital tube. The multivibrator circuit is composed of 555 timer, which provides clock input signal for synchronous addition counter.

Extended data:

Electronic counters can be divided into four categories according to their functions.

① General counter: measurable frequency, period, multi-period average, time interval, frequency ratio, accumulation, etc.

② Frequency counter: a counter specially used for measuring high frequency and microwave frequency.

(3) Calculation counter: a counter with calculation function, which can perform mathematical operations and can control all working processes such as measurement, calculation and display by programming.

④ Microwave counter: it is a microwave frequency meter consisting of a common counter, a frequency counter and a frequency measuring expander. The upper limit of frequency measurement has entered the millimeter wave band, and there are three types: manual, semi-automatic and automatic. Serialized microwave counter is an important aspect of the development of electronic counter.

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