Energy Content and Electromagnetic Force in Capacitors

Posted by Tomáš Zedníček
On May 7, 2020
0

Force action from electromagnetic fields. Parallel current-carrying conductors are surrounded by magnetic fields exerting forces on each other. If currents flow in the same direction the fields (and the conductors) attract each other. If the current flows in opposite directions.

ABC of CLR

Mounting Guidelines: Common Soldering Process Issues

Posted by doEEEt Media Group
On March 27, 2020
0

Fast oxidisation is a common issue related to high temperatures and the presence of oxygen during the convection reflow or wave soldering processes. The oxidisation may induce some degradation of metal surface and its environmental robustness, thus impacting the components and the electronic hardware lifetime.

ABC of CLR, EEE Components, PASSIVES

Thermal Noise, Current Noise & Corrosion on Resistors

Posted by Tomáš Zedníček
On March 6, 2020
0

Noise manifests itself as a spontaneously fluctuating voltage whose instantaneous amplitude is randomly distributed. The instantaneous value is both unpredictable and of minor interest except in certain critical applications. Instead, one measures a time-averaged value. It consists of the root of the mean-square value of voltage transmitted in a particular frequency pass band.

ABC of CLR, EEE Components, PASSIVES

Construction and Types of Wirewound Resistors

Posted by Tomáš Zedníček
On March 6, 2020
0

As the name indicates wire-wound resistors consist of a resistive wire wound on a bobbin and supplied with a protective coating. Since the resistance wire never can serve as a termination wire because of solderability requirements, it has to be connected to the terminal leads or the like, usually by welding or brazing. The higher the resistance value the thinner the wire that has to be used and thus the greater the risk of open circuits due to deficient weldings, damage from corrosion or from mechanical handling. Below a diameter, Φ, of 0.1 mm (4 mils) the failure rate grows rapidly.

ABC of CLR, EEE Components

Talking about Non-Wirewound Resistors: Carbon, SMD and Network

Posted by Tomáš Zedníček
On March 5, 2020
0

Carbon film resistors sometimes are called surface layer resistors. Better qualities are classified as “stable” with a ΔR/R that will stop at ≤1%. Their role has, to a great extent, been taken over by the metal film but they still have a market, especially as cheap 5 percent E 24 components. At new designs, one should yet consider replacing them with metal film resistors that also are offered in E 24, 5 percent.

ABC of CLR, EEE Components, PASSIVES, PHYSICAL, MECHANICAL & ASSEMBLY, TESTING

Mounting Guidelines: PCB Board Design and Handling

Posted by Tomáš Zedníček
On February 27, 2020
0

Board Design and Component Pre-Assembly Preparation The leads of leaded components shall be bent and often cut to the right length before they are mounted/soldered to the substrate. Lead cutting, bending and mounting are operations that may be hazardous if they are not performed properly.

ABC of CLR, EEE Components, PASSIVES

Film and Foil Organic Capacitors PET and PEN

Posted by Tomáš Zedníček
On February 27, 2020
0

The polyester film is most reliable and together with PP most used of plastic films. It can be produced in thicknesses down to 0.7 μm (0.03 mils). Its tensional stability is high and it’s εr ≈ 3.2. This has facilitated the manufacture of one for organic dielectrics very space-saving capacitor. A typical field of application is decoupling. Certain applications like switched mode power supplies (SMPS) require for filtering and decoupling purposes large capacitance and moderate losses which have made the MKT capacitor an attractive replacement for the relatively expensive ceramic X7R capacitors.

ABC of CLR, EEE Components, PASSIVES

Basic Principles of Potentiometers/Variable Resistors

Posted by Tomáš Zedníček
On January 30, 2020
4

POTENTIOMETERS Concepts and Definitions Potentiometers are electromechanical components and therefore exposed not only to the weaknesses of fixed resistors but also to all the failure possibilities of electromechanics. The reliability is comparatively poor. It will be even lower if we try to tool the shafts for our own special applications!!

ABC of CLR, EEE Components, PASSIVES

Derating and Category Concepts for Capacitors

Posted by Tomáš Zedníček
On January 14, 2020
0

Recommendation for voltage derating means that the actual capacitor shall be used in the application at a lower voltage than the rated voltage. Derating is expressed usually by percentage of rated voltage that shall be subtracted. For example, 20% derating means that the capacitor shall be used at 80% of rated voltage at the specific applications (10V capacitor to be used on 8V maximum).

ABC of CLR, EEE Components, PASSIVES

Potentiometers type 2

Posted by doEEEt Media Group
On January 8, 2020
0

Power potentiometers are as a rule wirewound. They are wound on a ceramic body and lack, due to heat dissipation concerns, encapsulation in casings or housings.

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