This frequency counter will provide a direct reading of the frequency applied at its input, through a 5 digit common cathode display module.
The compact frequency counter can be used for accurately counting the frequency or pulse from any intended source.
It can be also used for measuring the RPM of a rotating object by checking the digital 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 this digital pulse counter is for measuring the frequency of an inverter, or for checking the proper working of the oscillator of an inverter.
The project can be also applied in delay timer circuits for measuring the delay ON or delay OFF output pulse, and the time required for the output, to set the timing component values correctly.
About IC 4033
The IC 4033 is 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 digital display module. This IC is especially is extremely well suited in display programs which demand low power consumption and compactness.
A high logic on the RESET pin restores the decade counter to its intial zero display position. The counter is designed to move by a single count in response to the positive clock freqeuncy input when the CLOCK INHIBIT signal is provided with a low logic supply.
Counter progression by means of the clock rail is prevented and stopped as soon as the CLOCK INHIBIT is applied with a HIGH logic input.
The 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.
The 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.
The seven decoded outputs (a, b, c, d, e, f, g) light up the appropriate sections in a 7-segment display module intended for addressing the decimal figures 0 to 9.
The 5 digit 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).
The ICs used for this project are IC 4033, while the displays are 7-segment common cathode NTE3056 or similar.
The complete schematic of the proposed 5 digit frequency pulse counter is shown below.
The design is basically the identical repetition of 5 pulse counter stages comprising of IC1 and the DIS1 in a sequentially cascaded 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.
The 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.
If the frequency input is removed, the count over the display will get latched and remain available until the switch S1 is pressed, or the power is switched OFF and ON again.
PCB Design for the 5 Digit Frequency Counter
The following image shows the track side PCB layout for the 5 digit frequency counter circuit.