bipolar voltage switching scheme?
604716
Need to know a need or application. AC voltage by definition is bipolar. What are you trying to do?
430117
You could try this program out there called\nTRUE SWITCH.\n\nwww.trueswitch.com
341482
Ok break it down:\n1) A power supply converts AC power (110 in the states) to some other required voltage. For this (lab) project I'd presume a DC regulated voltage from, say 1.5 to 15V something like that.\n\n2) Digital and programmable means you'd control the output voltage with some sort of digital signal like up/down buttons, a keypad, or a PC hookup.\n\n3) You are supposed to use an 8051 to accomplish this.\n\nSo there are several ways to do this. One way would be to have the 8051 accept a command to set the voltage and produce a PWM signal. Let's say the PWM signal is a 5V output switched from 0 to 100%. You can use an RC filter to produce 0V to 5V from this signal. If your instructor is nice, you could argue that this meets the criteria -- especially if you use it to drive a pass transistor to develop some serious current (but your voltage is now 0V to 4.3V because of the BE drop).\n\nBut I'd instead use an op amp with gain X3 (plus a little extra) so that I got from 0 to 15.7V and then use the pass transistor. Another idea would be to use the voltage to drive a simple current source which would program a LM317 voltage regulator.\n\nWeb searches on things like LM317, PWM, and "pass transistor" are your friends here.
1038968
What voltage dc, or do you need to be able to vary it?  What current capacity do you need?  What ripple voltage is acceptable?
246250
A bistable multivibrator is a fancy word for a flip flop.\n\nSo there are several answers possible here. The easiest is to make the 4 transistors into two 2-input NOR or NAND gates and cross couple them (see below). Of course, that assumes by transistor you mean bipolar and not FET, but the ideas are the same either way.
786641
There are some battery management parts that look at 2 input voltages and are designed to give steady output if a part goes from being plugged in to battery. I'd check Maxim www.maxim-ic.com for some of their parts. You can always diode OR two supplies together, which will load share if equal, or give preference to the higher voltage if greater than the other by a diode drop.
990893
yes, it is a step-up circuit.\nYou can get many volts if you know what you are doing.
978617
Try this web page:\n\nhttp://hyperphysics.phy-astr.gsu.edu/hbase/electronic/zenereg.html\n\nIt shows the basic circuit and has calculator to figure out component values.\n\nThere are much better solutions out there for a voltage regulators than zeners... such as the three terminal regulators like 78xx or LM317 types...
508404
Use a darlington array. They make them with 6 or more darlington transistors on a single chip. Some even have the circuit protection diodes built in. These are perfect for stepper motor control circuits. If you don't want to buy them, you can probably scavenge a couple from a dead printer or copier, if you can get one.\n\nOther than that, there is no best transistor. This is a general, low speed switching application, and almost any transistor that can handle 160mA at your circuit's voltage can be made to work with the proper biasing. But a single chip to replace several transistors and diodes will simplify your PCB.
829788
It depends on the voltage your discussing.  The simplest that comes to mind is two parallel diodes reverse connected.  Silicon diodes will clip at  1.4Vp-p and germanium clip at 0.8Vp-p. \nFor higher voltages  two series zener diodes reverse connected will give you a wide option of clipping voltages. \nIf you specify the clipping volts I can help more.
418745
An uninterruptable power supply.  'UPS'
712591
Here's an idea. Make one that will shock people(low voltage) when they ring your bell. ;-)
376814
Goooogle\n\nhttp://www.karbosguide.com/hardware/module5a3.htm
934598
Try this website http://www.discovercircuits.com they have 1000's of circuits for all different applications
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.
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
580159
The AC Switch Block allows a conventional 5V signal to control a much larger AC line. The switch can handle up to 16 Amps of current provided it is kept cool enough. At 110V, this is more than 1500W. We suggest that this limit be approached very carefully and recommend staying far beneath this.\n\nOnce an AC line is connected to the AC terminals, several places on the board will become live. This makes it absolutely essential that the board be mounted in a way that will prevent short circuits and accidental human contact. This is true even for rough prototypes or trial hook ups. Treat AC line voltages with much respect.\n\nHow Do I Use This?\nWith your AC device unplugged, first determine which cable from your AC device's power cord should be switched. It's best to switch the "live" or "hot" wire. On any AC outlet, there are usually 3 slots (sometimes 2). The right slot, which is slightly smaller than the left slot, is the "live" slot - check which prong plugs into this slot when you plug the AC device in to confirm which wire is live.\n\nOnce you've determined which wire is live, snip it in two somewhere along its length, strip about 1/8" insulation away from both the open ends, and tin the exposed wires. Make sure to leave enough slack on the cord for the two tinned ends to be inserted to the two AC connectors on the AC Switch Block.\n\nA small 5V signal applied to the D0 input will control the switch that turns the AC device on and off. Run a wire from the 0V connector on the AC Switch to the ground of the device providing the 5V signal. Double check that all your connections are correct, and plug in the AC device to the wall - now, a 5V signal on the D0 input turns the device on and a 0V signal turns it off.\n\nApplications\n-Automate Your Household. Many household appliances such as lights, fans, blenders, drills, vacuums, etc. run on AC power. Now you can use the behavior from a Poly Block an Intro Module, or any other device that put out 5V, to control these kinds of devices.