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AN920
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Posts posted by AN920
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I had the same circuit in mind. Some of the small sensitive relays will switch on this method. You can use 5V relay to help with the switching. You may need play with the capacitor value to get the right action.
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But why can't you for instance log the specific offending IP and blacklist that? Rapidshare uses this method to restrict free downloads from their servers within a time frame. If someone on some occasion experiences a posting problem that can be handled on a case by case basis by emailing admin. If nothing is done this problem will just escalate.
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These spammers must be getting desperate if they now have to invade groups like this. I wonder how difficult it is for admin to just block their IP's from registering again. There must be a way to stop these idiots from spreading their filth here over and over again. They can easily register under another email but it is not so eay to alter IP's every time.
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Here are some hints:-
Square up your input frequency
Apply to the monostable to get fixed pulse width on every cycle
Filter the pulses with a low pass filter
Scale and calibrate output with opamp if needed
Voltage reading should be proportional to applied frequency -
Post your circuit cause you must be doing something wrong.
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Specify if you are talking about ideal cases or practical cases. If we know what you are talking about then we can give answers, otherwise it becomes confusing! At the moment I can't follow your reasoning.
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Into a 50 Ohm load
0dBm = 1mW
10dBm = 10mW
20dBm = 100mW -
I am not sure I understand the problem but you can use a comparator to switch high to 5V when the level of 1.43 volts is exceeded.
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The resonance conditions in the coax will happen only at a 1/4 wavelength (when the coax cable is 1/4 wl long)
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It all depends what you want to do.
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There are a few conditions of importance. Example:
1) for lines < 1/4 wavelength
50Ohm source into 50 ohm (Zo) line, OC at the end appears (capacitive)
50Ohm source into 50 ohm line, SC at the end appears (inductive)
50Ohm source into 50 ohm line, Rl at the end (Rl> Zo)appears (cap//resistance)
50Ohm source into 50 ohm line, Rl at the end (Rl< Zo)appears (ind + resistance)
2) for lines = 1/4 wavelength
50Ohm source into 50 ohm (Zo) line, OC at the end appears (SC)
50Ohm source into 50 ohm (Zo) line, SC at the end appears (OC)
50Ohm source into 50 ohm (Zo) line, Rl at the end appears (Zo*Zo/Rl)
3) for lines > 1/4 wl and < 1/2 wl
50Ohm source into 50 ohm (Zo) line, OC at the end appears (inductive)
50Ohm source into 50 ohm (Zo) line, SC at the end appears (capacitive)
50Ohm source into 50 ohm (Zo) line, Rl at the end (Rl>Zo) appears (ind + res)
50Ohm source into 50 ohm (Zo) line, Rl at the end (Rl<Zo)appears (cap//res)
where OC :-open circuit
SC :-short circuit
Rl :-Rload
cap//res :-cap and resistor in parallel
ind + res :-ind and resistor in series -
look on ebay. They go very cheap
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Anything to make the budget work will do! One guy refused to answer the door when they visited him and was fined $10000 for transmitting on 103MHz over the power limit.
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They do get caught, more quickly if they cause interference or there's a complaint. On the FCC page there is a massive list of all the instances of people caught or warned.
http://www.fcc.gov/eb/FieldNotices/
Ramsey was also fined many $1000's for selling high power (1W) transmitters. The FCC seems not to worry about their 25mW (FM25B)version. -
I read somewhere on a FCC page that the legal limit (88-108) in the US is something ridiculously like 15nW?? Enough to transmit 10'
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The RF power direct out from the BH1417 is low typically about 100dBuV or about -7dBm (0.2mW). The output impedance is 75Ohm and not 50Ohm as one will expect with most RF systems.
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They could have been from the same batch but I can't remember. I have also seen a frequency standard product that one company sold many of, that paralleled 3 or 4 of these regulators because of space problems. I own one and it's working for the last 5 years without failure. Can't say if they selected them especially for that purpose.
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I know there are many arguments about this issue of paralleling regulators. Looking at the internal structure of the LM7805 it looks possible to do this. Some time ago I experimented with true national 7805's and found that they do indeed share current when run near or at their maximum current ratings. I could not see any significant loss in voltage regulation running in this mode. The regulators that I tested had good thermal coupling close on the same heat sink. At lower currents the current sharing was poor. I don't know how well regulators from other manufacturers will perform.
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Plant number
Batch number -
The protection can activate with or without speakers connected. I this case my money will be on the protection circuit doing strange things.
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In most cases no picture means lack of high voltage to the CRT (picture tube). It is strange that you can still hear sound because in general the auxiliary windings on the EHT transformer power some of these circuits. Make sure there is high voltage to the tube by placing your hand on the tube face while switching the TV on and off. You should feel some static electricity. Also look for any sign of a flash on the screen when switching off in a darkened room. If any is present you have some high voltage to the tube. Another thing that may cause no picture is some sets is no focus voltage. You need a diagram to investigate this.
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Protection is activated when the sense circuitry determine a dangerous DC offset that may damage the speaker. The sense circuitry itself could be faulty and activate the protection relay. If you have a diagram you can make measurements to see what is going on.
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Most older HP/Agilent manuals in your test equipment section can be downloaded free from Agilent's website.
http://www.home.agilent.com/agilent/facet.jspx?t=80101.k.3&co=152502.i.1&cc=US&lc=eng&sm=g -
http://www.electronics-tutorials.com/oscillators/oscillator-basics.htm
http://web.telia.com/~u85920178/blocks/osc7m00.htm
Please help identify this part
in Electronic Projects Design/Ideas
Posted
FG looks to be mainly by Philips and Siemens.
http://www.tkb-4u.com/code/smdcode/smdcodeF.php