Oscillators are connected externally with the microcontroller to provide high frequency signal to the oscillator circuit in the microcontroller. The oscillator circuit provides the clock signal to the micro controller. Usually "PIEZO CRYSTAL OSCILLATORS" are used in micro controllers.
crystal oscilators mostrly of 11.05.... or 12MHz are used with microcontrollers,
SOME kind of oscillator is required, to create the AC signal that will be modulated, amplified, and eventually sent up to the antenna to be transmitted. It doesn't have to be a crystal oscillator, though.
pendulum spring tuning fork quartz crystal
Internally two crystal oscillator cycles are used as one single cycle. During one single crystal cycle it is made to logic high and logic low in next cycle so, that 50% duty cycle is maintained.
There are two kinds of crystal oscillators. One operates at what is called the "series resonance" of the crystal. This resonance is the frequency at which the (AC) impedance between the pins of the crystal is almost zero. The frequency is independent of how much capacitance happens to be in parallel with the crystal - its inside the oscillator and part of the circuit board, etc. But, even frequency that the oscillator runs at.The other kind of oscillator oscillates at "parallel resonance"of the crystal. At this frequency, the impedance from pin to pin of the crystal is almost infinite. This frequency depends on how much capacitance is connected in parallel with the crystal. This parallel capacitance is called "load capacitance". Generic signal-inverter oscillator is this kind of oscillator.The common oscillator connection is for the crystal to be connected from the inverter output to the input. And, there is a capacitor at each end of the crystal to ground. The NET load capacitance is SERIES equivalent value of those two capacitors.PLUS stray capacitance from the circuit board and the guts of the oscillator. Suppose that the crystal is rated for 22pF load capacitance. The stray capacitance is about 7pF. So, that leave 15pF to be made up from discrete external capacitors. If the external capacitors are equal, then their equivalent is half of their individual value. Thus, in this case, we would want a pair of 30pF capacitors.
crystal oscilators mostrly of 11.05.... or 12MHz are used with microcontrollers,
a crystal 32.768kHz oscillator.
oscillator frequency is different.crystal working piezo electric effect
YES
crystal oscillator
To increase the efficiency. Comparison between crystal oscillator and ceramic resonator.
"A circuit within a computer that creates a series of pulses that pace the computer's electronic system. The oscillator clock synchronizes, paces and coordinates the operations of the computer's circuit." -- webopedia
armstron osillator and work
The oscillator provides the basic clock of a microcontroller to be able to execute the instructions in a stable, periodic way. It is often used for other peripherals too, like timer, UART, etc. as frequency base, usually divided by a clock divider for integer factors, or by PLL for rational factors. If the timing accuracy of these functions is not important, a simple RC oscillator can be used. Many microcontrollers have it internally. Accuracy is in 1...10% range. For better accuracy and temperature stability, a resonator can be used. For applications where timing is critical, a crystal can be used. Most micros have built-in oscillator, so only a crystal and two caps are needed. For those which have no built-in oscillator, external crystal oscillator module may be used. There are OCXO and TCXO modules available for very high stability needs.
c1 and c2 capacitors with crystal eliminates the Harmonics(Unwanted frequencies) .
no
A crystal oscillator is often used in very delicate clock mechanisms such as those in high performance computers, medical equipment and sometimes even space technology for N.A.S.A.