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    sending a beep into the telephone line???

    Ugh, Without the AT?
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    sending a beep into the telephone line???

    (I am assuming US style phone system here so forgive me if I am off target) The phone line expects to see about 600Ohms per unit. The main issue I have always dealt with is the ON/OFF hook changes in the system. Idle the system sits around 60v Ringing is around 90VAC  @ 20hz Offhook and in...
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    confused about voltage regulator spec

    Remember your basics. P = E * I. If the Voltage into the chip is 9V and the voltage out is 5 then there is a 4V drop across the part. If the current flowing is 250ma then the wattage being expended at that part is 250ma * 4V = 1W If you drop that part in Liquid N (Assuming it can operate at...
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    A "silly" question about a resistor and a led position

    Kirchoff was wrong, and by gum I'll prove it dome day! ;D -Mike
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    Beginner's Question

    Vcc refers to the voltage applied to the COLLECTOR of a transistor. Most commonly in digital electronics that is POSITVE. Vdd is the voltage applied to the Drain of a FET.  The DRAIN is where the 'Holes' filled by electrons come from. It is positive  (While electrons flow from negative to...
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    What is the most common IC that People use???

    GREAT! ;D You and I can form a club.  I feel the same way quite often. Actually I'll bet most of us* feel that way a lot.  I work mostly with Communications and motor controls.  I use mostly Z80,Amtel, and PIC chips in my digital work but I have used "Basic Stamps" when I was in a rush and...
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    What is the most common IC that People use???

    mostly black ones with lots of pins.  ;D Seriously, what are you really looking for?  I doubt that there is a "Most Commonly used chip"  Schools are real heavy users of the 741 & 555 chips and the 3904 & 3906 BiPolars. Also the 1N4001 diode and the 7805 & 7812 regulators.  Most...
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    electronic wizkid needed!

    Laptop PCBs are subject to a lot of twisting and bending. All the talk about 'Titanium cases' isn't to make the case harder to crush or protect it from dropping.  The goal is to make the case as stiff as possible so the motherboard doesn't twist. Sony had a big problem with the PCB mounted...
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    Help me plz !!!

    My guess is to search for the ECAWA Robotics Special Interest Group. I did a web search but found very little in the way of a place to BUY the board. You could try to find the designer, "J Fuller". A final option is to check with some place like 'Gecko Drives'. They make a 3 Axis stepper...
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    Why? Supply pins position differ in Dig & analog IC's

    Yes, that would make it easier in many cases. :) Once in a while I have looked at a chip's pinout and wondered what the designer was thinking when they made the part.  ???  Later as I started to design a board layout I found that some of the pin placements were rather clever.  :D When...
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    Thinking about getting into electronics??

    In the US (My location) most consumer electronics are un-repairable. Actually you COULD fix them except for 2 problems:   1- The parts are usually very hard to find and sometimes can not be ordered in quantities less than 1000.   2 - The cost of paying someone to troubleshoot and then repair...
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    Feedback Theory!

    Output  = (Input * Feedback loop resistance ) / Input resistance) On a clean OP-AMP with a linear response it’s all easy. If you have some harmonics, or your circuit has some frequencies that Drop out or resonate then the response will be a little harder to predict. However that is not a flaw...
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    Interfacing circuits to the PC

    Parallel ports are about as straight forward as you can get in the electronics world. 8 wires / 8 bits. Unless you need it to be complex try to keep it simple. Bi-directional ports can be done but some computers require you to Select that mode in the Cmos. Check your machine before you get...
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    checking for proper earth grounding of wall outlets

    when it comes to line voltage in outlets I use a 'wiggy' that’s a brand name, I am sure there are other names for it. Electricians wouldn't be caught dead without one, In fact Without one, they might just get caught--- dead. A Multi Meter has a input resistance of about 20M ohms. This is...
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    CMOS gates

    Gates is gates. TTL runs at 5vdc ONLY.  Cmos can run at a wider range usually up to 15V and down to 3. You can mix TTL and CMOS at 5V. Most gates have 2 inputs and 1 output.  They come in packages that have 14 pins usually.  there are 2 power pins (Vcc and Gnd) The reaming pins are divided up...
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    Thinking about getting into electronics??

    Project management is the best part of being an EE? eeewwww. No the best part of life is when someone says,   "We need to change this design to add a new feature that everyone says   can't be done.  We heard you were the best, can you do it?" and you get to say, "Yes." The second best part...
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    urgent!help please?

    I wonder how r20552055 did with this project.  Sounded like he was in a hurry. (Odd, PWM motor drivers are usually not a rush project.) Just my 2ma worth.. I have been building for a long time and I finally learned that there are times when it is faster and cheaper to BUY parts rather than...
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    Interfacing circuits to the PC

    The RS232 standard uses 16V signals, however 12V is acceptable. The MAX232 chip uses 4 capacitors and some clever internal switching to convert a 5 volt supply into a 12V supply for the RS232 standard. Without the MAX chip you could use the 1466 Driver and the 1468 receiver plus a 12V power...
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    Thinking about getting into electronics??

    My Cynical Point of view:   What they are not saying is that Electronics Engineering is a very odd field. I am an EE.    I have yet to use so much as a Multimeter in my role because Most of my job is managing projects and PLC code review.  I also Write code for desktops and manage a corporate...
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    Interfacing circuits to the PC

    My personal choice is the Serial port. Parallel ports are getting rare on new machines and if you do use one you will need to run 8 data lines, 3 control lines (minimum) and you may have to fight the OS for direct hardware control of the port. USB is a very hard to use.  It requires a complex...
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