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  1. J

    Ideal Transistor for battery discharger

    As bob has stated, your best bet is to probably wire a set of transistors up in a darlington configuration. This will allow you to have as little base current as possible with the biggest gain. Bob already made it clear that the op-amp can not properly source enough current with the transistor...
  2. J

    Ideal Transistor for battery discharger

    Nope, not gonna work. You need that resistor there to set the current through the base which controls the C-E current. The transistor is an amplifying device,C-E current is proportional to B-E current. example: If you need 1A current going through the C-E junction and the transistor has a gain...
  3. J

    device to tap people's conversation

    See I knew in PA you could record telephone conversations that break the law without consent. Democracy at work people!!!
  4. J

    device to tap people's conversation

    Bobk, that is interesting. I live in one of those 12 states to. I was really unaware of that, but I do happen to know that in my state if you receive harassing phone calls you can notify the phone company and they have to track down the individual who made the phone call and notify the police...
  5. J

    Ring wiring circuits

    First thing I would do is see how much amperage is getting used when you turn on those items and the breaker trips. I have had this issue with 1970's electrical breakers getting weak over time and tripping under light loads. Is that electrical panel a stab-lock? You also don't need 10awg wire...
  6. J

    Project: Wireless transmitters

    I am not sure I can help either atm, but what is the difference between some wireless technology you plan on using compared to a design like zigbee that you won't use because it is not your own design?
  7. J

    APC UPS fault

    You are gonna have to explain a little more in detail what the problem is if you want help.
  8. J

    Preventing a 4013 'Setting' on Power Up

    Steve taught me this trick, Use an RC circuit to keep the clock input low for a few (m)seconds after initial power-up. It might help to see a schematic of what you have. The 4013 has a set pin, are you using this pin at all? again a schematic of what you have would help...
  9. J

    Ideal Transistor for battery discharger

    I think you have misinterpreted what harald has said. In the first link you posted, the drain - source on resistance is 10x that of the one harald linked to. sqr(10) = 20 * .06 = 1.2W of dissipated power. Not all mosfets are created equally. Note, it is not that you can't use the mosfet...
  10. J

    device to tap people's conversation

    Are you getting the harassing phone calls? Then by all rights you have every right to tap your own phone and record the messages to hand over to the authorities. Sorry I can't help you on the device, but don't concern yourself with legalities if it is your phone you are tapping. If you just want...
  11. J

    rectifer issues

    I get it, the connection where the two cathodes meet is the power rail. only one side conducts per half cycle of the AC
  12. J

    rectifer issues

    what would happen if you float the center tap and connect V- to ground? Dave, is it your point to get V- V+ power rails? edit: bobk answered me a minute before I posted my question. 2x the V half the current
  13. J

    317 reg

    Isn't the minimum voltage around 2.75V or something like that for a 317 VR
  14. J

    Circuit breaker lockout

    yep, just pull on the side without the wire attached. It will come right out, once out of the slot there is no power so you can unscrew the wire. Tuck the wire away, tape the end or put a nut on it to keep it from straying into a bus bar and making it live.
  15. J

    Diode Type

    Are the diodes gonna be forward or reverse biased? .550V * 7A = ~4W will be dissipated in the diode AFAIK. Remember current that doesn't flow is not dissipating any power if you are using the diode to block current flow.
  16. J

    repairing tv

    Really? You expect us to help you with that information?
  17. J

    Question on step motor control

    How many wires are coming from the motor, what are the other colors not connected to the motor? You could start by looking at the traces on the board and finding out where the power to the motor is connected and what wires/etc. are connected to the step and direction pins of the IC. If I was...
  18. J

    Unusual resistor calculator for electronic engineers

    So then this is spam? Your "market" is clearly people who might find this tool useful, they call that advertising! I think a mod can clearly close this thread now for what it is.
  19. J

    Just making sure

    No, as long as the two components are touching in some physical sense they you don't need a wire. This is why breadboards are so nice for prototyping. Pretty much just plug in your components and viola, no soldering or clipping stuff together. Radioshack sells breadboards!!! You put your chip...
  20. J

    Just making sure

    Pins 14-15 and 9-10. But you could just as well use 5-4 7-6 11-12. The chip has multiple inverters in one package, the design implements two of these inverters and leaves the other four unused. Which two he chose to use was probably dependent upon his PCB, where it was easiest based on chip...
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