Search results
Results from the WOW.Com Content Network
A tachometer (revolution-counter, tach, rev-counter, RPM gauge) is an instrument measuring the rotation speed of a shaft or disk, as in a motor or other machine. [1] The device usually displays the revolutions per minute (RPM) on a calibrated analogue dial, but digital displays are increasingly common.
The Fuller calculator, sometimes called Fuller's cylindrical slide rule, is a cylindrical slide rule with a helical main scale taking 50 turns around the cylinder. This creates an instrument of considerable precision – it is equivalent to a traditional slide rule 25.40 metres (1,000 inches) long.
On every range, at full-scale voltage of the range, the full current required to deflect the meter movement is taken from the circuit under test. Lower sensitivity meter movements are acceptable for testing in circuits where source impedances are low compared to the meter impedance, for example, power circuits; these meters are more rugged ...
If the circuit being measured can support the heating current, then it is possible to make a post-measurement calculation to correct the effect, as the impedance of the heating element is known. If the signal is small then a pre-amplifier is necessary, and the measuring capabilities of the instrument will be limited by this pre-amplifier.
Using a PMU, it is simple to detect abnormal waveform shapes. A waveform shape described mathematically is called a phasor.. A phasor measurement unit (PMU) is a device used to estimate the magnitude and phase angle of an electrical phasor quantity (such as voltage or current) in the electricity grid using a common time source for synchronization.
The arithmometer (French: arithmomètre) was the first digital mechanical calculator strong and reliable enough to be used daily in an office environment. This calculator could add and subtract two numbers directly and perform long multiplications and divisions effectively by using a movable accumulator for the result.
Its SI unit is the reciprocal seconds (s −1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). [ 1 ] [ a ] [ b ] Rotational frequency can be obtained dividing angular frequency , ω, by a full turn (2 π radians ): ν =ω/(2π rad).
Often called digital delay/pulse generators, the newest designs even offer differing repetition rates with each channel. These digital delay generators are useful in synchronizing, delaying, gating and triggering multiple devices, usually with respect to one event. One is also able to multiplex the timing of several channels onto one channel in ...