Oscillator free-running

That alone could be a reason why you would need this other feature, even if the free-running oscillation looked OK. 

In the free running oscillators, the basic frequency of oscillation is fixed by... 

While 50 O generators are generally on the order of 20% more expensive than the free-running oscillator type, they have some major advantages in certain circumstances ... 

The activities of the central processor are cyclical. The processor fetches an instruction, performs the operations required, fetches the next instruction, and so on. Such an orderly sequence of events requires timing, and the CPU therefore contains a free-running oscillator clock, which... 

A desirable feature of the free-running oscillator generator is the ease with which the plasma is initiated, making possible operation with minimal operator adjustment and few moving parts. 

Genmtors Crt vul ConcroUed Oscillator Free>Running Oscillator Solid-Sute Genetatots... 

A somewhat different view is supported by a number of other studies. Behavioural rhythmicity persists in SCN-lesioned rodents under the influence of either periodically available food (Davidson Stephan 1999, Stephan et al 1979) or continuous treatment with methamphetamine (Honma et al 1992). Rhythmicity of at least some circadian genes persists in isolated peripheral tissues for periods of time ranging from several days to two or three weeks (Yamazaki et al 2000, our unpublished results). Removal of the retina (which is known to contain its own circadian oscillator Tosini Menaker 1996) changes the distribution of free-running periods of locomotor activity and the duration of active time (a) (Yamazaki et al 2002a). To pursue our metaphor, these results suggest that circadian signals may be relayed to the periphery by a baton rather than a whip the SCN may indeed be the conductor of an orchestra composed of dozens, if not thousands of potentially independent oscillators. 

Menaker The interpretation of the eye experiment is much more problematic. The way I would like to interpret this is that there is an oscillator in the eye, and an oscillator in the SCN, and they are involved in a conversation. The consequence of that conversation is the value of the free-running period. 

Menaker Ralph Mistlberger has seen the same thing in SCN intact animals, which are free running in constant darkness and which are at the same time entrained to food anticipation. You can entrain them to 24 h and they will free run at 24.5 h, and these cross as if the oscillator is completely independent of the SCN. 

The astable operation of the UA555 as an oscillator has a duty cycle and free running frequency, which are both precisely controlled with two external capacitors and two resistors. The circuit is shown in Fig. 8.1. 

Broad band laser oscillation from Coumarin 153 doped ORMOSIL gels was easily obtained in the free-running laser cavity. The laser emission and the luminescence spectrum both peak at nearly the same wavelength as shown in Figure 4. The laser emission peak was at 526 nm with an oscillation bandwidth of approximately 20 nm FWHM. (For comparison, the reported total oscillation bandwidth in ethanol pumped at 308 nm is 75 nm.) The fluorescence spectrum has a broad peak at about 530 nm with a bandwidth (FWHM) of about 80 nm. 

Figure 4. Free running laser oscillation (A) and fluorescence (B) of C153 in ORMOSIL. The pump wavelength for both curves is 460 nm.

A 1- to 2-kW radio frequency power supply, either free-running or crystal-controlled, drives current through a water- or air-cooled copper tube that acts as the induction coil (often called a load coil). The oscillating current through the load coil produces an oscillating electromagnetic field. 

The various oscillators differ mainly in the feedback process used. The two main types of oscillator used in plasma spectrometry are free running and crystal controlled . 

These lasers operate mostly in the CW or free running pulsed mode and deliver output powers up to and exceeding 1 kW. They are configured as oscillators, but often have two or three laser rods in the resonator cavity. The resonator cavity is still approximately 1 m long, although the power supply is now significantly larger. Furthermore, these lasers, as well as some of the smaller lasers described... 

Free running An oscillator that is not controlled by an external synchronizing signal. 

---