The International Thermonuclear Experimental Reactor (ITER) tokamak is an experimental machine designed to harness the energy of fusion. ITER will be the world’s largest tokamak, with a plasma radius of 6.2 m and a plasma volume of 840 m³. The heart of a tokamak is its doughnut-shaped vacuum chamber. Here, under the influence of extreme […]
Visualizing phase relationships in capacitors
The ideal capacitor consists of two conductive plates separated by a thin dielectric layer that separates and insulates the two plates from each other so they have no direct or resistive electrical connection. When voltage is applied across the plates, they store the electrical charge. The capacitor may take many forms. If the plates are […]
Op-amps and their most important parameters
The operational amplifier (op-amp) has been one of the most successful integrated circuits. A type of differential amplifier with high gain, the differential inputs and single output enable this small, inexpensive IC to use negative feedback in a wide variety of applications, in which its gain (hundreds of thousands of times higher than the difference […]
Fluke test tools and protecting against arc flash
Fluke Corp. has manufactured electrical test and measurement instruments for decades, and these instruments have been well-known for accuracy, durability and great user-friendly interfaces. Maintaining those qualities, Fluke is now emphasizing electrical safety. This emphasis is apparent in Fluke’s new line of electricians’ hand tools, which are designed and built with the idea that after […]
Basics of cavity resonators
Experimenters beware! If you think it might be instructive to dismantle a microwave oven and power up the magnetron to make a space gun, don’t do it. A microwave gun (called a magnetron) in a state other than as manufactured has numerous potential hazards. (Nevertheless, you can find a lot of YouTube videos describing exactly […]
The difference between scanning electron microscopes and tunneling scanning electron microscopes
Compared to an optical microscope, the electron microscope achieves far greater resolution and magnification by taking advantage of the wave aspect of electrons. An electron’s wavelength is typically 1/100,000 that of visible light. Resolutions of 50 pm and 10 million-X magnification have been achieved, far better than the 200-mm resolution and 2,000X magnification of a […]
The difference between CCD and CMOS image sensing
Charge-coupled devices (CCDs) and complementary metal-oxide-semiconductor (CMOS) technology have been in fierce yet friendly competition. Fierce because valuable market share is contested, friendly because the rival digital camera technologies have much in common. It is ironic that the more-costly CCD sensor is used in the most advanced astrophotography instruments and also in low-end point-and-shoot cameras, […]
Testing PV inverters
A photovoltaic, or PV, inverter converts the dc output of a solar cell or array into ac that can feed directly into the electrical grid (Grid Tie) or be used by a local electrical grid (Off-Grid). Solar PV inverters have special functions adapted for use with photovoltaic arrays, including maximum power point tracking (MPPT) and […]
Tools for optimizing circuit bias
If a semiconductor or vacuum tube is to accurately reproduce or amplify signals on its input, it must have on its input a non-time-varying dc voltage, i.e. dc bias, the purpose of which is to keep the device in its linear operating range. Otherwise, the input signal to be reproduced may drive the device beyond […]
Difference between Cat 5e and Cat 6a cable
Cat 5e (enhanced) and 6a (augmented) are the most frequently-used media in residential and commercial Ethernet networks. Cat 6a has higher bandwidth and is faster, but the less expensive Cat 5e is often chosen when adequate for the application. It performs well up to 100 MHz. In contrast to coaxial cable, used in the first […]