FUSE RESISTORS

Written by Frieda Monday, 28 November 2011 08:43

A fusing resistor is designed to protect a circuit against damage as a result of current or voltage overload.  The resistor limits current flow and protects the circuit by opening (stopping current flow) when current levels exceeds its fuse characteristic design limits. The resistor serves the dual functions of a fuse and a resistor to limit the current.

Riedon fusible resistors are normally wire-wound resistor designed to open at power levels specified by the application.  These resistors must be specially analyzed and designed for a customer application in order to assure that the fuse opens under the right conditions and within the time duration specified by the application.

Please contact Riedon to discuss your fusing applications.  We would be happy to work with you to develop a product for your requirements.  Call us to get more information.

Surge Resistors – Are you looking for one?

Written by Frieda Wednesday, 24 August 2011 10:05

A surge resistor is a resistor installed in a circuit to prevent a “surge” when conditions arise where a surge might occur.

There are a number instances where energizing a circuit is followed by a surge of current. Like almost all the time. When that circuit “comes on” after the switch is flipped, current is flowing. And sometimes we need to place a resistor in series with the component or components that want to draw a ton of current on startup. We can look at a component that might just do that.

Capacitors (caps) are sometimes fitted with something that limits a big shot of current when a circuit is energized. Caps, you recall, begin operation in the circuit of a modern equipment uncharged, and when these caps are first “seen” by the voltage source at the moment it’s turned on, they look like a short circuit. Lots of current may want to flow. Jumping ahead, the cap sits in the operating circuit fat, dumb and happy “using” only a little current after things are going. But at startup, it needs to be checked to prevent it from “sucking up” (or sinking) too much current and overloading the supply. The surge resistor is on the job each time the circuit is energized.

There are other applications for a surge resistor, but the purpose is the same – prevent “too much current” from flowing at a given moment so the circuit can transition into a “normal operating mode” (where current flow is more modest).

The surge resistor is similar to a so-called current limiting (or, perhaps, ballast) resistor, but the name applied to the resistor in question might have more to do with the specific application. Wirewound resistors are perfect for high surge applications and Riedon offers one of the best “joule rated” resistors in the industry.

Riedon Introduces 3 New Products In Our Resistor Offering

Written by Frieda Monday, 11 July 2011 09:25

1) HIGH PULSE CHIP Riedon is well known for creating high quality joule rated wirewound resistors capable of handling instantaneous pulses of power. We are now extending this capability to our new PCR series, which is a pulse withstanding chip resistor able to withstand up to 4000W for 0.1ms. Compared to other competitors this rating is much higher. For more information on this resistor please click http://www.riedon.com/us/images/stories/pdf/PCR.pdf

2)ULTRA LOW OHM CHIP In addition to the PCR series Riedon would like to introduce the CSR series, an Ultra-Low Ohm (Metal Strip) Chip Resistor. We are introducing this to meet the increasing demand in the market for low ohm surface mount shunts. This type of device is used across many industries and applications including DC/DC converters, chargers, or adaptors, and power management for battery charging. For more information on this resistor please click http://www.riedon.com/us/images/stories/pdf/CSR.pdf

3) HIGH VOLTAGE MELF During the continued success of our precision metal electrode leadless face resistors, the MFM series, Riedon has found the need for a MELF that can withstand high voltages. In order to meet this requirement we would like to introduce the MFM series, a high voltage MELF resists that is able to withstand an operating voltage up to 3000V. This is nearly 9X higher than the MFM series, which can withstand up to 350V. To find out more information about this resistors please click here http://www.riedon.com/us/images/stories/pdf/MGM.pdf