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Universal had a number of industry "firsts", including such products as the "Dynamic Variable Resistance" technology that varied the resistance applied to muscle groups by an exercise machine throughout the entire range of motion. However, from the 1980s onward, Universal faced increasing competition from Nautilus and other rivals.
By 1970, a calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. The first handheld calculator was a 1967 prototype called Cal Tech, whose development was led by Jack Kilby at Texas Instruments in a research project to produce a portable calculator. It could add ...
This is the minimum value in the impedance vs. frequency relationship, which is always higher than the DC resistance of the voice coil, i.e., as measured by an ohmmeter. Minimum impedance is significant because the lower the impedance, the higher the current must be at the same drive voltage.
In the past, one or more vacuum tubes were commonly used as the variable resistance. Modern designs use one or more transistors instead, perhaps within an integrated circuit. Linear designs have the advantage of very "clean" output with little noise introduced into their DC output, but are most often much less efficient and unable to step-up or ...
A string potentiometer is a multi-turn potentiometer operated by an attached reel of wire turning against a spring, allowing it to convert linear position to a variable resistance. User-accessible rotary potentiometers can be fitted with a switch which operates usually at the anti-clockwise extreme of rotation.
See today's average mortgage rates for a 30-year fixed mortgage, 15-year fixed, jumbo loans, refinance rates and more — including up-to-date rate news.
Most analysis methods calculate the voltage and current values for static networks, which are circuits consisting of memoryless components only but have difficulties with complex dynamic networks. In general, the equations that describe the behaviour of a dynamic circuit are in the form of a differential-algebraic system of equations (DAEs ...
Series regulators are the more common form; they are more efficient than shunt designs. The series regulator works by providing a path from the supply voltage to the load through a variable resistance, usually a transistor (in this role it is usually termed the series pass transistor); it is in the "top half" of the voltage divider - the bottom half being the load.