Variables in Lead-Free Reflow for PCBs

Reflow ovens often show degrees of variability from profile to profile. This may depend on the distribution of components on the board, especially those that are slow heating, heat-sensitive, or of high mass. In general, reflow systems cannot generate one single reflow profile producing capable thermal results for all products. For instance, a large BGA package on the PCB may not allow more than five degrees of variation near the peak of the reflow profile curve. Therefore, even while the BGA Read more [...]

Storm Glass Lamp: Raspberry Pi Simulates a Storm

Several people have used the versatile single board computer, the Raspberry Pi or RBPi, as many types of educational devices. In fact, the original purpose of conceiving the RBPi was to use it as an educational instrument to further computer programming among children in schools. It has been serving this purpose excellently, and has managed to go even farther. For instance, the RBPi inspired someone to make a weather-simulation lamp for recreating the weather at any place in the world. The RBPi Read more [...]

Lead-Free Reflow for High-Layer-Count PCBs

High-layer-count multilayer printed circuit boards (PCBs) present one of the most difficult cases for adaptation to the lead-free reflow assembly process. Often, these boards have through-hole and hand-soldered components, along with the requirement for two or more rework cycles. The slower wetting and higher reflow temperatures of lead-free solders place an enormous strain on the laminates and copper-plated hole barrels of the vias, with resulting loss of reliability. Restrictions on Hazardous Read more [...]

How Counterfeit Electronic Parts and Components Affect Businesses

Although counterfeiting has been an age-old industry, it is only recently that the impact of counterfeit electronic parts and components has come to be highlighted. The public is slowly gaining the awareness of the implications and risks such counterfeited electronics bring to trusting users. It is difficult for manufacturers to trace the origin of the counterfeited parts compared to the traceability present for the authentic components. It is possible these are older, but legitimate versions Read more [...]

What are Flexible Heaters?

Everyone is familiar with heaters. Although the simplest forms of heaters are sunlight and fire, both are not easy to handle or control. Therefore, people prefer using electricity for generating heat, as this is easy to control, requiring only a switch to shut off or turn on. An electric heater generates heat by driving current through a resistive element. The power this arrangement consumes is the product of the resistance of the element and the square of the current flowing through it. The resistance Read more [...]

How is Solid Insulation Tested?

Engineers test solid insulation using two important test methods, and both use the Direct Voltage. One of the tests involves checking the resistance of the insulation, while the other tests the leakage current through the insulation at high voltages. Insulation Resistance Testing The instrument used for conducting this test is a megohmmeter. The instrument can be hand-cranked, motor driven, or electronic. Regardless of its principle of operation, a megohmmeter generates a direct voltage in Read more [...]

Expanding the GPIO on the Raspberry Pi

Although the single board computer the Raspberry Pi or RBPi has nearly 26 GPIO pins in its earlier models and 40 in its latest, there are times when the project demands more of them. In such cases, a GPIO expander is the only solution, and the MCP23S08, a device that Microchip Technology makes provides an easy way to expand the IO pins of a micro-controller using only a 2-wire serial interface. The MCP23S08 works with the I2C protocol as a slave device, providing 8-bit, general purpose, bi-directional Read more [...]

What are Memristors?

What are Memristors and where are they used? Professor Leon Chua developed the memristor theory in 1971. A scientist discovered the behavior of memristors when he was working in a lab at HP, trying to figure out crossbar switches. Memristors are also known as matrix switches, as they behave as a switch when connecting multiple inputs to several outputs. When Professor Chua looked at the assortment of resistors, capacitors, and inductors for the switching, he noticed a vital missing component, Read more [...]

How Black can VantaBlack be?

How Black can VantaBlack be? Any student of Physics knows that black surfaces are good absorbers of radiation of the visible and the infrared spectrum of light—they readily soak in visible light and heat rays. That is the reason they look black, as they reflect very little light. In fact, the amount of light reflected by a black surface is a measure of its blackness. Therefore, when VantaBlack, from the UK-based Surrey NanoSystems, is called blacker than black, there is a specific reason—it Read more [...]

Accurate Methods of Gas Analysis

Accurate Methods of Gas Analysis The earliest methods of detecting poisonous gases involved using birds such as canaries. This was mainly inside mines, where the presence of carbon monoxide, methane, and carbon dioxide had a harmful effect on the miners. The canaries, being sensitive to life threatening gases, would stop singing in the presence of such gases. This was a signal for the miners to evacuate. Modern methods use several other means of detection, and are more accurate. These involve Read more [...]