![]() ![]() So for example if we measure 800Hz with a known cap of C=100pf, then the unknown cap must be C/4 which comes out to 25pf.īut if we measured 200Hz, then the unknown cap must be 4*C=400pf, but we usually dont have to measure larger caps this way.104 capacitor in uf 104 capacitor value in uf 104 nf capacitor 10mm led resistor 12.5 uf run capacitor 1n5817 schottky diode 1n5817 schottky diode datasheet 2 zener diodes in series 2000 yukon blower motor resistor 2005 kia sportage blower motor resistor location 2006 ford explorer blower motor resistor replacement 2010 ford f150 lariat blower motor resistor 22nf capacitor 22nf capacitor code 22nf ceramic capacitor 250 pf capacitor 250 pf capacitor code 2n3055 npn transistor datasheet 3 in 1 hard start capacitor 3 phase induction motor construction and working pdf 3 phase induction motor ppt presentation 3 phase linear induction motor 300 ohm resistor amazon 4 band resistor color code 4 band resistor color code calculator 4 band resistor color code chart 4.7 k variable resistor 400w metal halide capacitor 470 ohm resistor smd 473 capacitor code 47uf 500v electrolytic capacitor 5 microfarad run capacitor 50 mfd capacitor price 50 mfd capacitor price in india 6 volt ballast resistor 8.2 k ohm resistor 8.2 k ohm resistor color code 8. If the original frequency was 10kHz instead, then just multiply all those frequencies by 10. Where C is the known capacitor here and the original frequency was 1000Hz. ![]() Here is a list of factors for 'new' frequencies of 900Hz down to 100Hz: ![]() So the unknown cap would have to have been 100pf also. If the new frequency happened to come out to 500Hz, then we would have: Where F1 is the frequency with only the known capacitor connected, and F1 is the new frequency with both caps connected. This means if we measure a frequency of about 909Hz then the unknown cap is about 10 percent of the known cap. So if we had a frequency of 1000Hz to begin with, the new frequency would be 1000*0.90909 which would be 909.09Hz which might show up as 909.1Hz. If we connect a 10pf in parallel with that we have: So say we connect a 100pf cap with some resistance (possibly variable) and we see a frequency of 1000.0 Hz. With a frequency oscillator like the 555 the frequency will be close to following the capacitor value in proportion to that capacitor value. Note that i had to take a reading first with the known capacitor. So here the x_pf (the unknown cap value) must be 9pf. Where Cp is the total capacitance and C1 and C2 are the two actual capacitors.Ĭ1 is the known capacitance which i take a reading first, and say i get 11pf, then C1=11pf, so then i parallel with unknown then get:Īnd say this second reading is 13pf, then we have:Īnd we all know that 13-11 is equal to 2, so the unknown cap must be 2pf.īut what if the unknown was higher. My $100 meter doesnt even go that low, but it can measure 10pf so i measure the 10pf and get a reading, then parallel it with 2pf and get another reading, then use the formula for two caps in parallel: Yeah, you can do it, but it takes special care. Disc capacitors are usually ceramic and for a 5 mm wide capacitor, 500V rating sounds reasonable, but do check manufacturers datasheet to be sure. That's almost like trying to measure a resistance of 0.001 Ohms. 470 is the code for 47pF, you need a code 471 for a 470pF capacitor. But seriously, 1pf is not easy to measure. ![]()
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