TT electronics' IRC Wire and Film Technologies Division’s SPP and SP Series are molded and conformally coated wirewound resistors and combination resistor/fuses. The product family consists of the SP20F (1-W molded fusible resistor), the SPF Series (2-W molded fusible resistor), the SP20 Series (1-W molded general purpose resistor) and the SPH (2-W general purpose molded resistor). The SPP Series are conformally coated, available in 1-, 2- and 3-W ratings.
The SP20/SP20F and SPH/SPF are constructed by winding a metal alloy resistance wire around a fiberglass core. End caps with welded leads are crimped to the wound core, then the units are encased in a molded phenolic shell. The SPP is similarly constructed, but uses a conformal silicone coating instead of a phenolic shell. The fusible versions feature a flame-resistant coating.
Standard resistance ranges from 0.1 Ω to 2400 Ω depending on wattage, with standard tolerances to ±5% and ±10%. IRC will also produce devices outside these specifications to meet customer requirements. Typical pricing for the SP20/SP20F and SPH/SPF Series resistors is $0.13 to $0.19 each in quantities of 10,000. The SPP Series resistors are typically priced at $0.10 each in quantities of 10,000.