Circuit Capacitance IC 555
This circuit is used for the frequency counter as digit number display, that can measure the period.To show a capacitance value of the capacitor directly.
If the
capacitor is connected that not know value onto a position Cx, then the period time will alter based on the value of Cx because RA and RB are a constant value.
If RA and RB are the appropriate period of time to read the meter, it will be the same as the capacitance of the capacitor. In with unit is picofarads, nano or microfarads.
For example, suppose a meter long periods of time with 1 second.
It’s meant to measure the capacity of one micro Farads. They will have all the values of RA + 2RB is 1.43 M.
Read value long as 1 seconds that value internal resistance of the capacitor, it will leak. As a result, the reading error.
In this case, it should take 1 second at 1000uF because value resistance of the capacitor size is less than 1000 times. If use with the frequency counter with 7 digits, it is displayed as 1000000 at 1 second. Equal to the value of 1000 microfarads. And at 1 microfarads capacity is displayed as 0.001000.