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Surface-mount technology (SMT), originally called planar mounting, [1] is a method in which the electrical components are mounted directly onto the surface of a printed circuit board (PCB). [2] An electrical component mounted in this manner is referred to as a surface-mount device ( SMD ).
An uncoiled modern watch mainspring. Clock mainspring A pendulum wall clock movement showing the two mainsprings which power it. This is a striking clock which sounds the hours on a chime; one of the springs powers the timekeeping gear train while the other powers the striking train
The general term is socket, but there are numerous common alternatives, including power point, [7] plug socket, [8] wall socket, [9] and wall plug. [10] Modern British sockets for domestic use are normally manufactured as single or double units with an integral face plate and are designed to fit standard mounting boxes.
The same timeline seems to apply in Europe, where mechanical escapements were used in clocks by that time. Up to the 15th century, clockwork was driven by water, weights, or other roundabout, relatively primitive means, but in 1430 a clock was presented to Philip the Good, Duke of Burgundy, that was driven by a spring. This became a standard ...
A synchronous electric clock does not contain a timekeeping oscillator such as a pendulum or balance wheel, but instead counts the oscillations of the AC utility current from its wall plug to keep time. It consists of a small AC synchronous motor, which turns the clock's hands through a reduction gear train. [9]
In this design, the motor proved to be much more reliable and was now an integral part of the movement rather than added on below the clock works. The "F" movement motor employed a vibrating up and down motion rather than rotary motion to re-wind the mainspring. SWCC imprinted all of their movements with serial numbers.
A clock driven by a synchronous motor is in principle as accurate as the line frequency of its power source. (Although small frequency drifts will occur over any given several hours, grid operators actively adjust line frequency in later periods to compensate, thereby keeping motor-driven clocks accurate; see Utility frequency § Stability.)
A flip clock (also known as a "flap clock") is an electromechanical, digital time keeping device with the time indicated by numbers that are sequentially revealed by a split-flap display. The study, collection and repair of flip clocks is termed horopalettology (from horology – the study and measurement of time and palette – and the Italian ...