ABSTRACT
This chapter looks at some passive component properties that are especially important in the design of small-signal audio equipment in general and active crossovers in particular. All passive components differ from the ideal mathematical models—resistors have series inductance, capacitors have series resistance, and so on. Active filters are the basic building blocks of electronic crossovers, and their proper operation depends on having accurate ratios between resistors and capacitors. Cermet resistors and resistor packages are metal oxide and are made of the same material as thick-film surface-mount (SM) resistors. Thin-film SM resistors use a nickel-chromium (Ni-Cr) film as the resistance material. Thick-film resistors can show significant non-linearity at opamp-type signal levels and should be kept out of high-quality signal paths. Wirewound resistors are indispensable when serious power needs to be handled. Through-hole (TH) resistors have the advantage that their power and voltage rating greatly exceed those of surface-mount versions.
