Pulse Width Modulation (PWM)
Pulse-width modulation (PWM) of a signal or power source involves the modulation of its duty cycle, to either convey information over a communications channel or control the amount of power sent to a load.Many digital circuits can generate PWM signals (e.g many microcontrollers have PWM outputs to control an electrical motor). They normally use a counter that increments periodically (it is connected directly or indirectly to the clock of the circuit) and is reset at the end of every period of the PWM. When the counter value is more than the reference value, the PWM output changes state from high to low. PWM can be used to reduce the total amount of power delivered to a load without losses normally incurred when a power source is limited by resistive means. This is because the average power delivered is proportional to the modulation duty cycle. With a sufficiently high modulation rate, passive electronic filters can be used to smooth the pulse train and recover an average analog waveform.
© Copyright Wikipedia Authors, 2007, Source: Wikipedia Radio Control Article, Under the GFDL license
In telecommunications and computer science, serial communications is the process of sending data one bit at one time, sequentially, over a communications channel or computer bus. This is in contrast to parallel communications, where all the bits of each symbol are sent together. Serial communications is used for all long-haul communications and most computer networks, where the cost of cable and synchronization difficulties make parallel communications impractical. Serial computer buses are becoming more common as improved technology enables them to transfer data at higher speeds.
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I²C is a multi-master serial computer bus invented by Philips that is used to attach low-speed peripherals to a motherboard, embedded system, or cellphone. The name stands for Inter-Integrated Circuit and is pronounced I-squared-C and also, incorrectly, I-two-C. I²C uses only two bidirectional open-drain lines, serial data (SDA) and serial clock (SCL), pulled up with resistors. Typical voltages used are +5 V or +3.3 V although systems with other, higher or lower, voltages are permitted. The I²C reference design has a 7-bit address space with 16 reserved addresses, so a maximum of 112 nodes can communicate on the same bus.
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The 'modern' potentiometer can be used as a potential divider (or voltage divider) to obtain a manually adjustable output voltage at the slider (wiper) from a fixed input voltage applied across the two ends of the pot.
© Copyright Wikipedia Authors, Source: Wikipedia Potentiometer Article, Under the GFDL license.
Radio control (a.k.a. R/C) is the use of radio signals to remotely control another device. The term is used frequently to refer to the control of model cars, boats, airplanes, and helicopters from a user-held control box (radio).
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