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  1. AnalogKid

    Need help with FM transmitter "adaptation" in photo

    Yes, VERY inaccurate. The resistor he indicated is *not* in series with the antenna. It is a 47 ohm terminating resistor to prevent reflections. The wire to GND that he added probably does nothing to affect the signal range. However, antennas are weird, and it might affect range by creating...
  2. AnalogKid

    Need help with FM transmitter "adaptation" in photo

    Where did you get that understanding? And . . . What is the original device? What device does it transmit to? Why do you need to increase its radiated power level? Note - the antenna might be a pc board trace on the underside of the board. ak
  3. AnalogKid

    Easy pulse generator

    Usually, an XOR gate with an R-C time delay is used to produce an output pulse for both the leading and trailing edges of the input pulse. What the TS wants sounds like a simple monostable that is triggered by the leading edge only. ak
  4. AnalogKid

    Easy pulse generator

    A single *logic* component, like one inverter or one two-input gate, sure. But any pulse forming circuit will need some kind of delay element or group of components to set the output pulse width. This can be as simple as one resistor and cone capacitor, as shown, or even a string of gates with...
  5. AnalogKid

    degraded while stored?

    Almost certainly no. But without a shred of information about the tube, that is just a guess. ak
  6. AnalogKid

    RC4558P opamp replacement

    Without the schematic it is impossible to be absolutely certain. You can check sources such as Electrotanya to hunt for it. The 4558 was a good part in its time, an improved version of the basic 741 concept. However, not long after it came out, Signetics dropped the NE5532 / 5533 / 5534...
  7. AnalogKid

    Interface connector help

    While the part in post #2 is intended to be inserted into a hole with the mounting flange on the outside, there is another way. Mount it on the inside of the box. This recesses the face of the connector by whatever the box wall thickness is. ak
  8. AnalogKid

    Can any help with a few electronic questions?

    This is not a free homework site. Please show us the work you have done so far to answer each question, and we will advise. The answers to all three questions are in any introductory book about electricity and electronics, using the most basic aspects of resistors and capacitors. Does your...
  9. AnalogKid

    Multi power supplies housing

    What in the world does that mean? Also, this thread died over three years ago. If you have a similar question, it is better to start your own thread, and reference this one with a link if necessary. ak
  10. AnalogKid

    Can’t figure out textbook graphic.

    Except for a factor of 1000, yes. The display clearly indicates ohms with no multiplier. Is the question oriented toward diagnosing a failed component? If so, the maybe kinda sorta changes everything. ak
  11. AnalogKid

    Can’t figure out textbook graphic.

    The bottom left resistor is 10 K, not 80 K. 80 K is not a standard E-24, 5% tolerance value. ak
  12. AnalogKid

    Which of the figure for DMA block diagram is correct? I am confused (confusion in comments)

    In the first figure, data transfers between memory and I/O through the DMA controller. DMA means Direct Memory Access, so it has a complete set of address and data bus transceivers to drive the memory array independent of the CPU. The three lines between the DMAC and I/O are the address, data...
  13. AnalogKid

    Help using NPN transistors as a switch

    Because there is no current-limiting resistor in series between the base and the 5 V source, you have blown the transistor. ak
  14. AnalogKid

    Electronics Hobby Magazines

    LOVE it - !!! ak
  15. AnalogKid

    Electronics Hobby Magazines

    The UK has Elektor, which I think still is in print. They have CDs and DVDs of their past decades. ak
  16. AnalogKid

    outdoor (Aqua) weather power points contain moisture, dirt and rusted screws

    What do you mean by "pips"? Photo? ak
  17. AnalogKid

    RS422 Help

    The gap between -2 V and +2 V is a dead band created by the Schmitt trigger input stage of the receiver. If the signal line rests within this band, the receiver output remains in the state of the last valid input. This is a way to increase noise immunity. If the signal that was sent is below...
  18. AnalogKid

    Electronics Boffins needed

    The transistor is underrated for the task. It has a max collector current rating of 500 mA, but all of the characterization charts stop at 50 mA. The relay coil draws 150 mA. If you must stay with a small signal transistor, consider a 2N4403. Adjust R2 for a base current of between 10 mA and...
  19. AnalogKid

    Electronics Boffins needed

    For firm saturation (lowest power dissipation), the old rule of thumb is that the ratio of a transistor's collector current to base current should be 10:1. But this isn't the 1950's, so I start with 20:1 - ish. Start with Vcc. Subtract the base-emitter junction voltage (Vbe). Subtract the...
  20. AnalogKid

    delay on timer

    Only bipolar 555's; and, again, not when running on 3.3 V. CMOS versions are rated to run on 3.3 V, but can deliver only 10/50 mA. See bertus's partial datasheets above. I want to update my previous response, but am locked out. It would take a *p-channel* MOSFET with a low threshold voltage...
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