### Straightforward Frequency Meter

Straightforward Frequency Meter
Here is a straightforward recurrence meter with which input recurrence can be controlled by just measuring the estimations of two resistors and a smidgen of calculation.
A re-triggerable monostable multivibrator and a D flip-slump can shape a basic, yet solid recurrence comparator that contrasts an info recurrence and a foreordained reference. To figure out if an info recurrence (f) falls between two known frequencies, f1 and f2, two one-shot/flip-flip blends are utilized, as appeared. Here both the one-shot and the flip-tumble ICs are wired for positive-edge activating. Every info beat causes the monostable's yield to go high for the time of its preset planning interim. The flip-slump is activated all the while, yet its yield is dictated by the condition of its D contribution at the time of trigger limit.

In the event that the time of the information recurrence is shorter than the preset planning of the monostable, a consistent abnormal state will be available at the D input, driving the flip-flounder's Q yield to stay high. In the event that the input recurrence period gets to be more prominent than that of the monostable, the flip-flounder's Q yield will go low. VR1, VR2, and C1, C2 decide the estimation of the day and age of f1 and f2. Some run of the mill values for measuring a scope of information frequencies is given in Table 1. One approach to gauge the recurrence is to increment f2 by diminishing the estimation of R2 until LED3 goes "off" and LED4 goes 'on'. At that point R1 is lessening so that LED1 goes "on" and LED2 goes 'off'. Presently both LED1 and LED4 gleam and the estimation of R1 and R2 are measured. Frequencies f1 furthermore, f2 are figured by the formulae f1 = 1/(1.1R1C1) and f2 = 1/(1.1R2C2) furthermore, the information recurrence "f" falls in the middle of f1 and f2. On the off chance that f1<f f2<f It can be further noticed that the estimations of the resistors and the capacitors can be taken concurring to one's application.

PARTS LIST
Resistors (all ¼-watt, ± 5% Carbon unless expressed generally)
R1, R2 = 10 Ω; VR1, VR2 = 4.7 Kω
Capacitors
C1, C2 = 10 μF/10V
Semiconductors
IC1 = 74123, IC2 = 7474 LED1 – LED4 = distinctive shading LED</f</f