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原帖由 ljm_ljm 于 2007-8-22 14:51 发表 ![]() % \: R3 U' @5 e1 y& e
我从来不觉得胆机失真大会好听。说夸张点，可以说我从来没觉得电子管好听过。
- c" r- Z0 z+ M( `4 Hw00t) 也许是我比较喜欢新的科技技术，说电子管好听的。有机会去听听140DB 动态的大录音制作室就知道。电子管原来是XXX。" I; c$ W- {/ N7 p: b0 n* \
; \- q1 x# F+ G) y/ W7 c& G9 M至 ...
3 [8 t" v) q/ q: O+ K* q l o0 x查了一下介质损耗的资料。好像就是ESR除以容抗。
# i7 V6 Y+ o" k( w+ ?" d3 C- f; X2 q, _# b. B1 Z7 k
Dissipation factor is measured at 120 Hz, up to
3 X5 {, ^ S5 U' m2 z1.0 volt rms maximum, and up to 2.0 volts DC
& { ` y/ N# n' l5 A" Jmaximum at +25°C. The application of DC bias) ]; B6 f! t6 R' ?+ J L/ y; u% [
causes a small reduction in DF, about 0.2% when
7 `9 J$ L- I. o7 C& Bfull rated voltage is applied. DF increases with# G: g: X- u$ s6 P% b
increasing frequency.2 \/ x4 x' ^4 f! R
, u! _, t$ M" `! s4 aDissipation factor is a very useful low frequency
+ V0 l5 a; ^) u6 O: K(120 Hz) measurement of the resistive component+ a2 J3 R0 w8 R0 A& n3 g
of a capacitor. It is the ratio of the equivalent series
% j9 |! R: i" ]' j l; P2 _& Fresistance (ESR) to the capacitive reactance, (XC)
& ^1 [1 `" _8 [3 F+ k7 D. Dand is usually expressed as a percentage. It is
; C7 i3 r* x0 |! D9 Tdirectly proportional to both capacitance and frequency.
* z. y- S8 C: gDissipation factor loses its importance at
% X6 h0 B2 H+ Chigher frequencies, (above about 1 kHz), where
) s' w6 p) z; b Mimpedance (Z) and equivalent series resistance
& ~ M& d- ?- C+ S! G& Z6 ^) K(ESR) are the normal parameters of concern.
7 }5 |8 _/ A" ^4 w+ b& C; U& i# ?& z' B x; o4 {9 {) c
DF = R/XC = 2pifCR2 ]( q' \) j! x# T& T
DF = Dissipation Factor* w* M: {: u4 H. Z4 i8 C3 K' \* ^6 ^
R = Equivalent Series Resistance (Ohms)# U) Z3 W7 L& Y4 s. ]/ C. g
XC = Capacitive Reactance(Ohms)
* k! S( l E" H( f( f7 M0 _f = Frequency (Hertz)- S# }9 D' c9 X
C = Series Capacitance(Farads)
, z; ~2 v' e0 I) V$ H
f, Y2 k; `1 d( WDF is also referred to as tan or “loss tangent.”
) y' O2 v: {, }* YThe “Quality Factor,” “Q,” is the reciprocal of DF.
6 i4 H, l7 K! e, `DF decreases with temperature above +25°C and$ V! ?0 A) ^+ p% ]
may also increase at lower temperatures.$ `& T) O# @! [9 ]
Unfortunately, one general limit for DF cannot be' v3 P; u7 n% c# H: D+ @; O
specified for all capacitance/voltage combinations,
( F1 d3 ]/ g ^" H7 u) z4 q9 Bnor can response to temperature be simply stated.
( z$ J* Z. H4 {. Q+ HDC bias is not commonly used at room temperature, C8 e+ C; [- m1 |
but is more commonly used at elevated temperatures. |
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IP卡
狗仔卡
楼主
显身卡
发表于 2007-8-22 01:31
