======================COMPONENTS_CAPACITORS================================ capacitor material Aluminium Electrolytics: 1. Cheap per farad 2. Small per farad 3. Drifty 4. Limited life (they dry out, especially if hot) 5. Leaky 6. Poor at mid and high freq. 7. Tolerance: poor 8. temperature range: restricted Tantalum Electrolytics 1. Cheap, but not as cheap as Alum 2. Small, but not as small as alum 3. Drifty, but better than alum 4. Better life than Alum 5. Less leaky than alum 6. Good up to high audio freqs. 7. Tolerance: better than alum 8. temperature range: better than alum, PolyEster (mylar) 3. much less drifty than electrolytics 4. much longer life 5. very low leakage 6. usable up to RF 7. Fairly tight tolerence available 8. temperature range: good at low temps,can melt Ceraminc. Low 1. Cost: high per farad 2. Size large per farad 3. Drift: among best 4. Life: long 5. Leakage: very low 6. Usable freqs: RF 7. Tolerence: very tight 8. temperature range: wide 9. Voltage: very high available Medium 3. Drift: better than electrolytic, worse than polyester 4. Life: long 5. Leakage: low 6. Usable freqs: RF 7. Tolerence: moderate 8. temperature range: wide High 3. Drift: very 4. Life: long 5. Leakage: low probably (not sure) 6. Usable freqs: low RF 7. Tolerence: medium to poor 8. temperature range:restricted high and low Aluminium Electrolyt Cheap/Small/Leaky/Drifty/Limited life,dry outhot Poor mid ->high freq, seen in power supplies. Tantalum Electrolyt Cheap/Small/Drifty/Less leaky/Better life/ Good up to high audio freqs. Tolerance: better PolyEster (mylar) much less drifty/much longer life/very low leakage usable to RF,Fairly tight tolerence ,can melt Ceraminc Low best Drift/very lowLeakage /very tightTolerence temperature/voltage range wide, long life For RF,High cost Ceraminc Medium Tolerence moderate, Drift worse than polyester Ceraminc High very Drift: low RF Tolerence: medium to poor Metialize film caps advantage at self heating and size deposit metal in liqified state to dielectric surface mylar inexpensive but temp dependent polycarbinate low freq dependence . low temp effect electroylics caps +75% -10% 80% -55C 112% at 125C electroylics imped 300(R*C) 0dB at 300c and 20dB at -55C electroylics leak 5uA -> 30uA at 125C Ceramic caps up to 100MHz Micra up to 200MHZ polystryrene up to 200MHZ mylar inductance Q Energy_stored/energy_loss Rp/sqrt(L/C) RS*RP=L/C Q number of cycles to settle silver mica max 0.1uF stable ,expensivve ceraminc up to 1000MHz CAPACITOR 10|..C............................ | C . . . L . | . . L . | C . L . . | C. . L . . | C . L . . 1|.........C......L.............. | . C .L . . | . C L . . | . C L . . . | . R . . . | . . . . .1|............................... | . . . | IMPEDANCE OF 0.1uF . | . . . . | . . . . | . . . . |_____________________________ . 100KHz 1MHz 10MHz 100MHz 1GHz size_uF freq_MHz Rmin Polyester caps 1.0 2 .02 Polyester caps 0.01 20 .1 ceramic dip caps 1.0 2 .03 ceramic dip caps 0.01 20 .2 tantalium 47.0 .1->3 .2 tantalium 4.7 10 2 Electrolyte CAP Electrolyte _ Alum Oxide Dielectric soaked paper | | V V _ _ || | | | || _____|| | | | ||_____ |_____ | | | | | _____| cathode || | | | || Anode foil || |_| |_|| 1) etch foil 2) grow oxide with voltage applied 3) thickness =0.06E-6 in/V_applied _ _ _ /*\/ \/ \ ___ ESR | () () | ___ wound core 150uF | |_/\ _____||__| 100uH |_| | resonate 10KHz 100KHz |___| \/ | || | |___| | | |_/\ __| \/ DCL ESR equiv_serie_r decreases with temp .1 to 10ohms DCL direct_Current_Leakage a function of temp voltage (if reverse V high current,decrease Cap ,higher DCL) max temp 65C to 85C up 30% cap -30C =-60% cap with increase in ESR age cap cap drop with age 75->73 DF dissiaption factor =(2*PI*F*C)*(ESR)/1E4 PF power factor =ESR/Z Ileak_max (50nA/(uF*V))*(rated_C)*(rated_V) for C<1000uF*1V about 5uA (30nA/(uF*V))*(rated_C)*(rated_V) +20uA for C*V <1000uF