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5#
发表于 2010-2-6 09:23:10
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来自: 广东中山 来自 广东中山
你在1.2V的地方加了电容 那1.2V的开启顺序会比之前的要慢,我帮你找了下资料 是以前我们公司老外发的邮件 给你参考 RC delay circuit delay time calculation formula 2009-09-10 07:53 formula:
Delay time = - R * C * ln ((E-V) / E)
Where: "-" is a negative number; resistor R and capacitor C are in series, R units of ohms, C in units of F; E for the series resistance and capacitance between the voltage, V for the capacitor voltage to be achieved between. ln is the natural logarithm, in the EXCEL system has a function to calculate very convenient.
After comparing the actual calculation is consistent.
For example: R (150K) and C (1000UF) between the voltage of 12V, when the capacitor C bipolar voltage of 3 volts when the time:
=- (150 * 1000) * (1000/1000000) * ln ((12-3) / 12) = 43 (seconds)
RC charging circuit according to the formula: Vc = E (1-e-(t / R * C)) the projection
R = 2.2KC = 100PF. Supply voltage of 20V. I want to know both ends of capacitor voltage from 0V to 13V up the time spent T how calculated? This more practical, initial state and final state have the
13 = 20 (1-exp (-Td/RC));
13/20 = 1-exp (-Td/RC);
7 / 20 = exp (-Td/RC);
ln (7 / 20) = -Td/RC;
Td = 1.0498 RC; |
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