voltage controlled oscillators?
966403
It depends on the application.\nDr. Boye's requirement for the VCO was that it produced 5 distinct types of audio signal waveforms: square, sawtooth, triangle, sine and a pulsed sine wave that had a duty cycle of 3 seconds on and 3 seconds off. \nhttp://www.phy.davidson.edu/instrumentation/VCO.htm
415600
You can't.\n\nFirstly, I think you mean a potentiometer, not a rheostat.\n\nThere are two types of tuning arrangements.\n\nOne of them uses inductors and a variable capacitor (usually a dual-gang one.)  This is an analogue system.\nYou can't modify the tuning range with a pot.  \n\nThe other type uses a frequency synthesiser, which is a digital system.  Not a digital radio - a digital tuning sytem.\nYou can't use a pot to modify the tuning range of that either.\n\nIf you have a good understanding of frequency synthesis in general, and a good understanding of a particular receiver's\nsynthesizer, you might just possibly be able to achieve what you want to do.\n\nBut, the naivety of your question suggests to me that you stand no chance whatsoever.   Sorry.
1065990
In Electronics Physics:\nthe use of an oscillator feedback loop as a power supply. Add a bridge rectifier to the output and feed the DC current Resistance limited back to the oscillator amplifier setup. Like using an auditorium feedback signal to drive the DC system.
824800
You can use an integrated circuit, like LTC6906 from Linear Technology which goes up to 1MHz at 2.25 - 5VDC supply,\nsee:  http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1010,C1096,P9790,D6998\nAlternative: MAX5094A by Maxim,  see:  http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5017\nI didn't have the time to check the output power, but if it's not enough, a simple emitter stage transistor will do.
863589
Wave shaping circuits are used in function generators.  You might get some help here http://en.wikipedia.org/wiki/Function_generator
831663
Variable voltage and frequency drives operate by first converting the incoming ac (typically 50 or 60Hz) into dc.  Then the drive controller uses this DC to generate an AC output that has the proper frequency to turn the motor at the desired speed.  The voltage output is varied depending on the amount of load on the motor.
842468
Simple voltage regulators, threshold detectors, voltage limiting circuits, voltage references, discriminators, pulse shapers, noise suppressors and the like.
399288
If you mean the programable logic controller...most plc's now required 24VDC to operate.
264474
http://electroactive-polymers.brainsip.com/ - Try this website. It contains a complete description of what you are looking for.
888482
Please contact your local professional service centre.  \nDo not scratch your head with V= I X R.\nIf you still want to do your self,  use single phase varioc.  \nvoltage from 0. \nNormally Fridge comes with 230 volts input in India, \nrest of the world, I don't know.
1177002
yeah you can use a switch (voltage switch) or if you can use binary logic, need to know how much voltage/current you are dealing with
159857
this si not a physics question. this is a basic IC that perhaps still and certainly at one time was available at radio shack. the ic 741 behaves as ANY op amp and it is electronics 101.......happy homeworking.
191766
Have you thought of looking into Radio Shack...they have just about anything....good luck!
219996
This site has a wealth of information. I often use it as a starting point when looking for a new type of circuit:\nhttp://www.discovercircuits.com/list.htm
100843
I hope this helps:\n\nhttp://www.tivocommunity.com/tivo-vb/showthread.php?s=&threadid=128743
745937
On band radios I assume. There are many such sites on google.com that list them. Radio shack will also help you.
410833
An electronic oscillator is an electronic circuit that produces a repetitive electronic signal, often a sine wave or a square wave.\n\nA low-frequency oscillator (or LFO) is an electronic oscillator that generates an AC waveform between 0.1 Hz and 10 Hz. This term is typically used in the field of audio synthesizers, to distinguish it from an audio frequency oscillator.\n\nThere are two main types of electronic oscillator: the harmonic oscillator and the relaxation oscillator.\n\nThe harmonic oscillator produces a sinusoidal output. The basic form of an harmonic oscillator is an electronic amplifier with the output attached to a narrow-band electronic filter, and the output of the filter attached to the input of the amplifier. When the power supply to the amplifier is first switched on, the amplifier's output consists only of noise. The noise travels around the loop, being filtered and re-amplified until it increasingly resembles the desired signal.\n\nA piezoelectric crystal (commonly quartz) may be coupled to the filter to stabilise the frequency of oscillation, resulting in a crystal oscillator.\n\nThere are many ways to implement harmonic oscillators, because there are different ways to amplify and filter. For example oscillator variations include: Hartley oscillator, Colpitts oscillator, Clapp oscillator, Pierce crystal oscillator, Phase-shift oscillator, RC oscillator (Wien Bridge and "Twin-T") \n\nThe relaxation oscillator is often used to produce a non-sinusoidal output, such as a square wave or sawtooth. The oscillator contains a nonlinear component such as a transistor that periodically discharges the energy stored in a capacitor or inductor, causing abrupt changes in the output waveform.\n\nSquare-wave relaxation oscillators can be used to provide the clock signal for sequential logic circuits such as timers and counters, although crystal oscillators are often preferred for their greater stability.\n\nTriangle-wave or sawtooth oscillators are used in the timebase circuits that generate the horizontal deflection signals for cathode ray tubes in analogue oscilloscopes and television sets. In function generators, this triangle wave may then be further shaped into a close approximation of a sine wave.\n\nThe multivibrator and the rotary traveling wave oscillator are another types of relaxation oscillators.