Staigen

Hi I checked on the net, the gate capacitance is 1259 pF/fet, thats a plenty of pF when multiplied with 25! The 555 cant feed that much current needed for a fast switch! //Staigen

Hi Madame A 555 can NOT feed 25 mosfets, it can not deliver that much current needed to charge/discharge the gate capacitance! They did not have enogh skills! ;D The coils should be at the same leg I dont think it will work! You must do something to the gate drive first! Then test, you will only loose 25 Fets at max! ;D ;D //Staigen

Oops, i must be tired! ;D ??? You dont need a computer, use a microcontroller insted, complete with interface to the periferals! For the camera system, use a camera and a monitor! Also you need to program the microcontroller! //Staigen

Hi there mainbrain, velcome to the forum Ok, where did you found it? Url? //Staigen

Hi there mohammed Ok, i will help you a little(point you in some directions) First, i think, you need some kind of solenoid/motor or something to control the locking/unlocking/opening/closing of the door. Second, a button/keypad/cardreader or similar to check the person that will enter the door. Third, obviusly you need some kind of camera. Fourth, you need a computer. Fifth, some kind of alerter to alert the security man. Sixth(right spelling?), you also need som kind of interface between the computer and periferals, at least some of them. Seventh, you also need some kind of operating system for the computer Eight, you also need some kind of programming tool to write a program to control the whole thing. Maybee you need some moore things that i have forgotten, wiring for example! You also need a lot of luck! ;D ;D //Staigen

Hi all of you I have been thinking for a while, cant we(at least those of us that are active) go together and construct some instrumentation and other stuff, make them good, discuss them together, and upload them as projects here on this site? For example you, Audioguru, have a good tone generator, i belive. And a funktion generator can be handy sometimes. A signalgenerator can be good for them that are into HF. A front end for a wideband oscilloscope connected to a computer can be handy. And so on, there are much moore, i belive. //Staigen

Hey madame Have you checked out how they do it in computer PSU:s( AT, ATX ) ? BTW, steel plates for the core? Will that work? And dont it seems to be a very big core? //Staigen

Hi ArabicEdison You can control up to 256 relays, and with a little clever thinking you can control as many relays you want! Try this: http://www.kemo-electronic.com Choose the english version(i hope you understand english)! ;D Observe! They dont sell to private persons! We can try ;D

Hi there ArabicEdison If you click on the "home" button you can change to an english version of the site( i hope you understand the english language) ! ;D //Staigen

Oscillating? Check with your scope! A cap on the output wouldn't hurt! //Staigen

Hey Shahriar, where is the base-emitter resistor for the 2N4403 transistor, it must be one for cirquits like this ;D //Staigen

Hi If the line is horizontal then it is the frame output that is at error! Alkv23, is the line horizontal or vertical? //Staigen

Hey Mukhalled, you must use AC to measure the impedance. In this case you also must use several freqs to get a usable measurement, say at 100 Hz, 200 Hz, 400 Hz, 800 Hz and so on, but i would not do it that way, i would have used 3 or 5 amps, one for the subwofer and the others for the other speakers. //Staigen

Ok, go ahead! :) //Staigen

Hi Mukhalled, how did you measured the impedance of the speakers? Audioguru, dont you think the amp #2 is going to be slant loaded by the subwoofer speaker? There is speakers with 2 voicecoils, specially made for this purpose. The right way to do it, i belive, is to use one amp for the subwoofer and an active filter and a summing amp before that. //Staigen

Hi Ok, that amp is bridged, what is the impedance of your speakers, and do they have crossovers buildt in? //Staigen

Hi Mukhalled Is the amps bridged? And do you have crossovers connected to the speakers? //Staigen

Hi Glen

Ok, then it is a cap :) //Staigen

Hi Of course i mean the TV Antenna mixer PCB, i hope the PC motherboard dont have something to do with your Antenna Board! ;D //Staigen

Hey Audioguru, take a look at the first one you linked to, what is the 555 doing there? Also look at the resistor divider, isnt that one backwards? And, why 74193? A 40193 is the same, and cmos! There are many moore errors there! /Staigen

Hehe, yeah, the BC548 wasn't born at 1965, but i belive BC108 was(BC107, BC108, BC109) //Staigen

Hi Shahriar I dont think so, i belive it is some kind of tuning cap or impedance matching, what is it on the other side of the PCB? //Staigen

Hey Audioguru, did you use BC548C 40 years ago? //Staigen

Hi Glen :) Did you? I tried to YAHOO it and got 62000 hits, but of course, i spelled communication right ;D But i did know how household slow data communications worked already :). Its like this, usally. A high frequency is superinposed on the AC line. This frequency is usally in the range 40 Khz to 200 Khz. This frequency is then usally FSK modulated by the data transmitted. At the reciever end then this frequency is demodulated and data recovered. There is also other types of Powerline Communications! Example: Broadband data communications, analog communications, and so on. //Staigen