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[SOLVED] What is the difference between a crystal and an oscillator

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skyglin

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difference between crystal and oscillator

Both elements are used for providing clocks to a system, I know that an oscillator can generate its own clock signals, and a crystal needs an accompy oscillator for the generation of clock signal (am I wrong?). If so, can we use an oscillator to provide clock to a microcontroller(such as those PIC devices) directly since in terms of price the cost between a crystal and an ocillator doesn't differ a lot? So, why almost all the projects I've seen on PIC microcontrollers uses either a crystal or a resonator?

skyglin
 

difference between oscillator and crystal

Oscillator is a circuit that oscillates. There are many types of it.

We can say that crystal (usualy quartz crystal) is used to make the oscillations of oscillator very accurate. This oscillators are called crystal oscillators.

Hope this helps.

eblue
 
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    eehadi

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oscillator crystal difference

Hi

A Crystal or Ceramic resonator is the core of a ossilator and makes it possible to get a precise frequency , but they need to be drived by either a transistor or a inverter plus normally a few small caps.Most microcontrollers , PICs etc have the driving circuits built in so all you need to add on the outside is the Crystal or resonator, but on most micro's you can also drive the clock pin with a external ossilator( you will have to check the datasheet of the device to see.

Regards
G
 
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difference between crystal and crystal oscillator

An external oscillator can be used to provide a clock signal to a MCU. Look at the datasheet of the MCU. But for example PICs are often used in Sleep mode to save battery power. In this mode the oscillator has to be stopped to save the current of some mA. This can't be realized with an external oscillator.
Another aspect of using a resonator - assumed the accuracy is sufficient - is to save money in a high volume market. Example: if a resonator is 10 cent cheaper than a crystal and you produce let's say 100000 peaces, an amount of 10000EUR or $ can be saved - why not. Talk to your boss about that :wink:


Mik
 
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what is difference between crystal and oscillator

In Simple words, A on chip osciilator can be a crystal oscillator. A crystal starts oscillating once you bias it.
 

difference oscillator crystal

A crystal is a simple piece of quartz. You have to design a circuit to make it oscillate. For example, when you use a micro-controler, you have 2 pins for xtal, you put your crystal on those 2 pins, and put capacitors from those 2 pins to GND (usually 18~35pf).

When designing other circuits, where you wish to make a oscillation source, you may have to add more components.

On oscillator is like a small module, that you simply put voltage across 2 leads, and a 3rd pin oscillate. So, you don't need external circuitry.

Though, depending on the target chip you wish to use, you have to make sure that if you use a 3.3V device, that the oscillator is 3.3V rated.
 

crystal oscillator difference

Hi~~

The frequency characteristics of a crystal shows a very very narrow bandwidth for it to operate as an inductor. If you replace an inductor in an oscillator appropriately with a crystal, then, it will also work as an oscillator, where the oscillation frequency lies within the very very narrow bandwidth. Since the temperature dependency of the frequency characteristics of a crystal is very good compared to other components, they usually adopt a crystal oscillator.

Bye~~
 
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crystal and oscillator difference

It is worth mentioning that oscillator circuits are of specific design. You just pick the oscillator you want and plug in the values. I would bet that the characterstics are very good with any oscillator. Some have frequency limitations to them. If you choose the crystal oscillator, that is your choice and the design is well published.
 

difference between oscillator and resonator

Oscillator is the general term for circuit that provide oscillation frequency (audio or radio frequency). For digital applications its normally refers as clock frequency.

You can get oscillation (oscillator) either by using discrete component (capacitor, inductor, resistor or crystal) or an ic like 555.

For microcontroller application (depending on type of uc) you can use RC or Crystal. Crystal clock normally requires 2 additional capacitors to run. With ceramic resonator, all built in (crystal (?) and capacitor)
 

difference between crystals and oscillators

Crystal is a devide to generate the one freguency per one crytal that each crytal not same does.but Oscillator is generate the several frequency.
 

difference crystal oscillator

hi, regarding to the oscillator, xtal is one part of it. there are more than one type of oscillator, such as the RLC oscillator, xtal oscillator, so on.

one of the advantages xtal oscillator has over the RLC is that with xtal, we can get a high and very accurate oscillating freq.
 
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difference between clock and oscillator

h**p://www.ieee-uffc.org/freqcontrol/quartz/vig/vigtypes.htm
Take a note on the, for example, Pierce circuit. The crystal and capacitor arrangement is the same as how we normally connect to say, a PIC or AVR... The rest of the circuit as been mentioned before is embedded inside the microcontroller.
 

difference between crystal & oscillator

As others above have explained, an oscillator is a self-contained module that outputs a square wave at the desired frequency. A crystal needs a surrounding circuit to be useful, typically for PICs, a Pierce circuit with neighboring capacitors going to ground.

An oscillator is more expensive and draws more power, but doesn't depend on the accuracy of other components in the circuit.

**broken link removed** explains the trade-offs between crystals, oscillators, resonators, RC circuits, and others.

This explains the difference between all the crystal parameters you might see, like "Series vs Parallel", "Load capacitance," "Series Resistance," and more.

This Microchip application note explains important design trade-offs in selecting crystals for PIC applications, including how the LP, XT, and HS PIC settings affect power use and startup ability.

**broken link removed** gives some abbreviated guidance for how the neighboring capacitors affect things and also explains PPMs.
 
different between oscillator and crystal

An Osilator is a chosen selection of components that produce an osilation.
A crystal is a single component that naturaly reonates at a specific frequency.
 

diff crystal oscillator

An oscillator is anything that produces a periodically varying signal,it can be a circuit,mechanical device, whatever,but output (voltage) values repeats in cycles after fixed tme period.
For an oscillator the most important factor is the period of oscillation. To get accurate periods without much variation, most commonly used devices are piezo-electric crystals like quartz.These produce electrical signals when mechanically stressed, and vice-versa.
When a crystal of say quartz is properly cut and mounted, it can be made to mechanically distort in an electric field by applying a voltage to an electrode near or on the crystal. This property is known as piezoelectricity. When the field is removed, the quartz will generate an electric field as it returns to its previous shape, and this can generate a voltage. The result is that a quartz crystal behaves like a circuit composed of an inductor, capacitor and resistor, with a precise resonant frequency.
 

difference between a crystal and oscillator

An oscillator is any circuit that produces a stable waveform. there are several types, RC,LC, XTL etc. a XTL crystal on the other hand is a piezo ceramic material component that can help in design of an oscillator. In a computer for example, the timing is generated by a XTL oscillator
 

Re: difference between a crystal and oscillator

Hello,
my 16c62A/JW is connected this way to the crystal resonator.
How should I connect it if using one of these crystal modules? What changes to the circuit?
 

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You remove the capacitors and feed the clock in to OSC1. You also need to change the microcontroller configuration settings to use an external oscillator instead of a crystal.

Keith.
 
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keith1200rs said:
You remove the capacitors and feed the clock in to OSC1. You also need to change the microcontroller configuration settings to use an external oscillator instead of a crystal.

Keith.
Click to expand...

OSC2 and VSS are left unconnected?
 

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