Tel:400-803-9333

Chinese English

  • Welcome to Microhm
Current Limiting Resistor and Pull-Up Resistors

Current Limiting Resistor and Pull-Up Resistors

A current limiting resistor is the one used to reduce the current present in a circuit. A simple example is a resistor in series with a LED. You would usually want to have a current limiting resistor in series with the LED to control the amount of current flowing through it, else the LED will burn due to it exceeding its current limit. Microhm Electronics shunt resistors, like MMS2512, can be used for this application. Pull-up resistors are resistors commonly used in logic circuits to help ensure a well-defined logical level ...

Date:2019-08-12      [More+]
Resistors' Frequency Response

Resistors' Frequency Response

When considering resistors, resistance is not the only important thing to think about. Like any other component there are a number of important things to consider. Microhm Electronics recommend resistors according to the resistance, tolerance, power, TCR, size and type demanded mainly. Frequency Response is also one of the key parameters to consider in certain special application, like radio frequency (RF). Ideally, resistors should act as pure resistors, without any of the characteristics of other types of component and whe...

Date:2019-08-09      [More+]
Method of Current Measurement — Shunt Resistors Vs. Hall Effect

Method of Current Measurement — Shunt Resistors Vs. Hall Effect

Two most commonly used technologies in photovoltaic power plants operating sensors include resistive current shunt sensor (shunt resistor ) and current sensor for magnetic field ( Hall Effect ). As a leading supplier of shunt resistors, Microhm concentrates on the current sense applications. Resistance shunt provide an accurate and direct measurement of the flow, but do not offer any galvanic isolation. The shunt current is the least expensive solution available today for current measurement. A shunt consists of a precision r...

Date:2019-08-08      [More+]
Making Sense of Current Sensing Resistors

Making Sense of Current Sensing Resistors

Apart from current sense monitoring using a resistor, like Microhm current sense resistor MMS Series, two other less common methods are used. One uses a Hall Effect sensor to measure the flux field generated by a current. While this is non-intrusive and has the advantage of no insertion loss, it is somewhat expensive and requires a relatively large amount of PCB real estate. The other method, using a transformer to measure induced AC current, is also size and cost intensive; while also useful only for AC current. If using a r...

Date:2019-08-07      [More+]
What is Resistor Derating and the Factors Impacting It

What is Resistor Derating and the Factors Impacting It

The nominal power rating is defined for a certain ambient temperature in free air. Note that the amount of energy that a resistor in practise can dissipate without causing damage, is strongly dependent on the operating conditions and therefore not equal to the nominal power rating. For example, a higher ambient temperature can significantly reduce the power rating. This effect is referred to as derating. It should be taking into account by the designer. Often the power rating is chosen largely above the electric power. Typica...

Date:2019-08-05      [More+]
Metal Foil Resistor Construction

Metal Foil Resistor Construction

Surface mount foil resistors are commonly produced as two terminal devices with solderable wraparound terminations. They are available in a variety of standard footprints including sizes 0603 up to 2512, like Microhm Electronics MPR series, NMS types. The typical surface mount foil resistor consists of a flat, rectangular, insulating substrate (e.g., alumina) on top of which the resistor element is bonded using adhesive materials (e.g., resins or polymers). The resistor element is made from proprietary nickel-chromium based a...

Date:2019-08-02      [More+]
Metal Foil Resistor Characteristics

Metal Foil Resistor Characteristics

Metal Foil Resistor is an important part of Microhm Electronics product linup. We offer surfact mount type, like NMS2818,NMS4527,NSR series and MPR series, as well as radial type, including To247 type resistor, To218 type resistor and MVR series. The excellent properties for precision and stability are due to a combination of several characteristics, which are following from the design principles of the metal foil resistor. Foil resistors achieve a low TCR by taking advantage of two characteristics of the foil. The resistance...

Date:2019-08-01      [More+]
Shunt Resistor Current Sensing Method

Shunt Resistor Current Sensing Method

Selecting the proper method for current sensing is not a difficult thing. There are few factors need to be considered for choosing the right method, like: 1. How much accuracy is needed? 2. DC or AC measurement or both? 3. How much power consumption is required? 4. What is the current range and bandwidth to be measured? 5. Costing. Other than those, acceptable sensitivity and interference rejection are also need to be considered. A low-value resistor in series is used to sense the current. When the current flow through a low-...

Date:2019-08-01      [More+]
microhm@microhm.commicrohm@microhm.com