operation of emitter follower?
371859
An emitter follower has a voltage gain of very nearly 1 and a high current gain. It is connected with supply voltage Vcc at the collector and the load resistance between the emitter and ground. The voltage at the base will be nearly exactly reproduced at the emitter but there is a base-to-emitter voltage drop Vbe which is about 0.6 volt for silicon transistors. Vbe is nearly constant as long as the transistor is not driven too close to cutoff or saturation. The input impedance is high because of the transistor's current gain (called beta). For AC (e.g., audio) amplification, you typically bias the base at Vcc/2 which allows a signal swing of nearly + or - Vcc/2.
866935
http://en.wikipedia.org/wiki/Transistor\n\nIt's a big subject, at that is just a start.
774945
It is the line connecting Vcc/Rl and Vmax on the transistor VIcharecteristics V on the x axis and I on the Y axis. Where it cuts the charecteristics we get the quiscent point or the operating point. This is the mean point,  the output current varies sinusoid beyond and below this point on the load line.
469104
The algebraic sum of the currents entering a node is equal to zero. Where current entering is positive and exiting is negative (or vice versa). In other words, what comes in must come out.\nNote: this is only true for DC signals.
244997
An operational amplyfier has a gain of one.Thetrefore it is very ussefull in logic circuitry.
290867
I think you are talking about the alpha coefficent of a bipolar transistor. This is the ratio of emitter current to collector current. So, since Ie=Ic+Ib, if the ratio was >1 then Ib would have to be negative! Which would turn the transistor off (assuming an NPN here).\n\nSo A=Ic/Ie = (Ie-Ib)/Ie So must always be <1 if Ib>0.
130649
A common emitter circuit has the emitter grounded (not necessarily to DC, but at signal frequencies via a capacitor).  In an oscillator, the feedback is from collector to base.  Common emitter circuits are, um, commonly used configurations, as they provide both current and voltage gain.  A common collector circuit, e.g., an emitter follower, has current gain but a voltage gain slightly less than 1.  A common base circuit (seldom used) inputs signal at the emitter and outputs at the collector, and has voltage gain, but a current gain slightly less than 1.
169792
A typical output has a transistor that pulls the output to ground when the output is 0 and a pull up resistor or transistor that drives the output high when the output is 1.\n\nHowever, there are two cases where this might not be desirable. Suppose we have an inverter that we want to use to turn on a 12V light. Sure, you could use a transistor or other switch to do that, but why not use an open collector inverter. This inverter only has the "low side" transistor. So the output is either 0 or floating. If the chip can handle 12V on the input, you can use it to directly turn the light on (it will be on with the output low). The 12V supply would go to the bulb and the other side of the bulb would go to the open collector output.\n\nThe other reason to do this is when you want to drive a lot of outputs into one input. For example, suppose I'm building a CPU. I have an input that causes a register to write its content to the bus. Further, suppose there are 10 reasons you might want to do this. The obvious way is to have a 10 input "OR" gate so that when any of these 10 things occur, the register gets the signal. But an easier way is to make the input active low. Tie a pull up resistor to the input and then drive it with 10 open collector gates. When no one wants to make the register write, the outputs all float and the resistor holds the input high (no action). If any output goes low (or multiple outputs, for that matter), the input goes low and the action occurs. This is often known as wired-OR.\n\nYou might find The Art of Electronics useful. You can read my review of this fine book at http://www.wd5gnr.com/books.htm (I didn't write it, BTW).
421929
This is a basic form of feed-back controller.  You create an "error" signal, based on the difference between a desired state, and a measured state.  In your example, this would be the distance the joint is from the target position.\n\nYou apply a gain to this error signal, to provide the driver signal to the actuator.  In the case of PD, two gains; one to the Difference (the error) and one to the change in the error, since the last measurement/control cycle.\n\nThe gains are not dimensionless, and in your example, assuming voltage controlled actuators, the dimensions of Gp are volts/meter.  The dimensions of Gd are volt seconds/meter.\n\nok?  For more, see the reference source below.
859562
www.learnelectronics.com
960408
http://www.eas.asu.edu/~holbert/ece201/kvl.html
131607
Wow, I can't believe you have been waiting so long for an answer.\n\nThere are a couple of papers you can review:\n\ne.g. http://www.nsti.org/publ/MSM2002/348.pdf#search='frequency%20mosfet%20parameter'\n\nand here also:\nhttp://www.freewebs.com/anishamukherjee/Papers.htm\n\nThere is a tool here, but you need to pay, and I have not used it myself:\n\nhttp://www.highbeam.com/library/doc0.asp?docid=1G1:79591050&refid=ink_tptd_mag_test1&skeyword=&teaser=
262059
It isn't an open circuit in steady state, only in DC. Steady state means the transient signal is gone. If the signal is time-variant, it acts as 1/(jwC).\n\nAnd it doesn't just filter NOISE, but any undesired frequency; it 'tunes' a system so you get a desired frequency response.
480313
Monolithic microwave amplifiers are widely used in the industry for signal amplification. The majority of these amplifiers are specified to operate with fixed current. In the real world of low voltage supplies, fixed current is difficult to realize. Normally, a constant-current source is approximated by a voltage source, RF choke and a resistor.\n\nthe typical specifications of these amplifiers. One significant feature is that they can be operated over a wide voltage range, 2.8 to 5V. This makes them useable for battery powered applications\n\n\n\nhttp://360.yahoo.com/jcbroogley
870052
Full example and circuit diagram on http://www.padre.ca/house/multiplier_example_web.pdf
150653
http://www.cs.uiowa.edu/~jones/step/circuits.html\n\nyou might consider buying the chips that do most of the hard part unless you are trying to learn how they work in which case that link is just perfect.
797986
This is a very simple circuit.\nhttp://www.rason.org/Projects/fmkeyer/fmkeyer.htm