5位数频率计数

该数字频率计数器将通过5位公共阴极显示模块直接读取其输入处应用的频率。

这compactfrequency countercan be used for accurately counting the frequency or pulse from any intended source.

Main Applications

它也可以用于测量RPMof a rotating object by checking the digital frequency reading with a corresponding stop watch. The reading on the display after 1 minute will provide the user with the RPM value of the source.

Another useful use of thisdigital pulse counteris for measuring the frequency of an inverter, or for checking the proper working of the oscillator of an inverter.

该项目也可以应用于delay timer circuitsfor measuring the delay ON or delay OFF output pulse, and the time required for the output, to set the timing component values correctly.

关于IC 4033

这IC 4033is composed of a 5 stage Johnson decade counter and an output decoder which is designed to convert the Johnson code to a 7 segment decoded output.

This decoded output is used for driving a single stage of a数字显示模块。This IC is especially is extremely well suited in display programs which demand low power consumption and compactness.

重置引脚上的高逻辑可将十年的计数器恢复到其Intial零显示位置。该计数器的设计目的是在为正时钟Freqeuncy输入中响应单个计数而移动，当时时钟抑制信号的逻辑供应较低时。

一旦抑制时钟抑制，就可以防止时钟导轨的反进度，并停止使用高逻辑输入。

这CLOCK INHIBIT logic input could be applied as a negative-edge clock in case the clock line is applied with logic high. Antilock gating is offered within the JOHNSON counter, which ensures correct sequencing for the counting process.

这CARRY-OUT (Cout) signal finishes a single cycle every ten CLOCK INPUT cycles and it is implemented to clock the next up decade instantly in a multi-decade counting chain.

七个解码的输出（a，b，c，d，e，f，g）在7段显示模块中点亮了适当的部分，该模块旨在解决小数数0到9。

Circuit Working

这5digit frequency counter circuit discussed below is made using five decade-counter IC's (IC1 through IC5) and their complementing 7 segment displays (DIS1 through DIS5).

这ICs used for this project are IC 4033, while the displays are 7-segment common cathode NTE3056 or similar.

这complete schematic of the proposed 5 digit frequency pulse counter is shown below.

这design is basically the identical repetition of 5 pulse counter stages comprising of IC1 and the DIS1 in a sequentiallycascaded format。

It must be note that DIS2 is the only display module which has an active decimal point. This decimal point illuminates as soon as the supply to the circuit is switched ON.

这frequency or the pulse which needs to be counted and displayed over the 7-segment displays is applied to the pin#1 of IC1.

As soon as the frequency is applied, the displays begin showing the number of elapsed pulses of the frequency.

如果频率输入删除,计数the display will get latched and remain available until the switch S1 is pressed, or the power is switched OFF and ON again.

5位数计数器的PCB设计

下图显示了5位数字频率计数器电路的轨道侧PCB布局。

10 MHz数字频率计

Figure 1 exhibits the circuit diagram of the 10-MHz digital Frequency Counter. The circuit includes an ICM7208 seven-decade counter (U1), an ICM7207A oscillator controller (U2), and a CA3130 biFET op amp (U3). IC U1 is used for counting the input signals, and then decode them to 7-segment structure. It additionally is used for generating the output signals for driving a 7-digit LED display.

IC U2连接以为U1提供定时时钟，而U3则处理输入信号以提供适合U1输入的波形。5.24288 MHz晶体的频率除以U2，以在U2的引脚12处生成1280 MHz多路复用信号。该信号应用于在其引脚16上的U1的输入，该输入可连续扫描显示位数。每个数字的阴极每秒反复切换到地面，触发由于U1的解码而导致其阳极高的任何段。

这frequency from the crystal is additionally divided to generate a short "store" pulse on pin 2 of U2, which is followed by a brief "reset" pulse on pin 14 of U2 (after around 0.4 milliseconds). The pulse frequency is established by the state of the pin 11 of U2.

一旦U2引脚11通过S1切换到地面，脉冲每2秒重复一次，并导致U2引脚13旋转一秒钟。这抑制了进一步的输入信号进入U1。这导致内部计数器中的U1的锁存计数发送到显示模块。IC U2的PIN13随后将一秒钟变低，允许将新的计数插入U1的七个十年计数器中。

重复该期间，每2秒钟不断更改显示器。当U2的引脚11切换到正电压（ + 5V）时，“存储”和“重置”脉冲开始在0.2第二个时间段开始发生，创建了0.1秒的计数时间段。它需要对10个输入脉冲进行计数，以确保第一个数字出现在第一个数字D1上，因此测试的频率显然比在7个段模块上显示的频率大10倍。在此设置中，小数点由R1提供动力，并在视觉上表明已应用0.第二个计数周期。

Testing

To quickly test the working of the 10 MHz digital frequency counter circuit, apply a sample frequency which can be under 100 Hz. Put a momentary jumper to connect U1 pin7, 23, or 27 with the + 5V as advised through the dashed line displayed in the first circuit doagram. IC U1 after that implements the count for all digits greater than D2. Data for U2 signifies that C1 can be a trimmer or variable capacitor. Having said that, a 22 pF fixed disc capacitor can work reasonably well for the majority of applications, and offers precision to .005 %.

Begin by setting the range switch to "1 second", implement the multiplexing frequency from U2 pin 12 to the input of U3, and fine-tune the trimmer to get a reading of 1280 Hz.

测量频率

当S1位于1-秒模式下时，计数范围为1 Hz至1 MHz，这将提供从显示屏上直接读取。如果S1移至0.1秒位置，则测量范围将增加到10 Hz至10 MHz。结果显示在显示屏上的数字为1/10的频率的1/10（1 kHz显示为100）。

如果您尝试测量一个新频率，则一读将变成以前的频率，该频率已在计数器中锁定。

You will have to wait for 2 or higher count intervals for the circuit to stabilize around the newly applied frequency.

另外，您可以尝试按RESET开关（S2），直到显示“ 00”显示为止，然后您可以释放开关。