Boone, N.C. Providing design engineers with cost-effective resistors for power circuits where board space is at a premium, resistor manufacturer IRC now offers economical wirewound devices that are rated at double the power dissipation of traditional axial-leaded packages. Designated the SP/SPP series, these power wirewound resistors are also available in fusible and flame-resistant versions.
Applications for the SP/SPP series resistors include power supplies, motor controllers, televisions, consumer electronic products and appliances, as well as general-purpose power circuits. The resistors can also be used as drop-in replacements for carbon composition devices in certain applications.
The SP20 series resistors are rated for 1 W at 50°C, with resistance values from 0.1Ω to 1,200Ω, in standard tolerances of ±5% and ±10%, with temperature coefficient of resistance (TCR) ratings as low as ±150 ppm/°C. The SPH series resistors are rated for 2 W at 70°C, with resistance values from 0.1Ω to 2400Ω, in standard tolerances of ±5% and ±10%, with TCRs as low as ±150 ppm/°C.
The SP20 Series resistors are rated for 1 watt in a package typically associated with half-watt devices, while the SPH is rated for 2 watts in a one-watt package. "This kind of power density in a low-cost resistor gives design engineers increased flexibility in their power electronics circuits by enabling them to specify a smaller device that can meet their power and surge requirements," said Keith Chipman, product manager for IRC's Wirewound and Film Technologies Division, in a statement.
The SP20/SP20F and SPH/SPF devices are constructed with a metal alloy resistance wirewound wrapped around a fiberglass core with welded end-caps and sealed with a molded phenolic material. It's also marked with solvent-resistant color bands. The SP20F and SPF devices are fusible versions that feature a flame-resistant coating.
The SPP series resistors are rated for 1W, 2W and 3W at 85°C, with resistance values from 0.1Ω to 2,400Ω (lower ranges available), in standard tolerances of ±5% and ±10%, with TCRs as low as ±300 ppm/°C. They are constructed with a metal alloy resistance wirewound around a fiberglass core with crimped end-caps, conformally-coated and marked with solvent-resistant color bands. The SPP series can also be produced as a fusible resistor by request. Custom specifications are available.
Typical pricing for the SP20/SPH 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. Delivery is from stock to six weeks.
IRC Wirewound and Film Technologies Division, 1-828-264-8861, www.irctt.com