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  1. hevans1944

    LM386 replacement

    You could possibly do the attenuation (two resistors) external to the PCB. Or tack one between the input and common on the PCB and connect the other one in-line with the signal source wire. If this is a production product that could add considerable labor and possibly make it non-competitive to...
  2. hevans1944

    help..can you tell me the value of this capacitor?

    Woo woo! That big, they probably are 1650 pF = 0.00165 μF! These were probably intended for use as resonating or RF by-pass capacitors in some sort of power electronics equipment, like an ultrasonic cleaner maybe. Dipped micas are premium capacitors, once favored by hams who built tube-type...
  3. hevans1944

    Laser specifications help

    Could you elaborate on exactly what "a burning laser pointer" is and what you intend to do with it?
  4. hevans1944

    LM386 replacement

    Why not just attenuate your input by a factor of five?
  5. hevans1944

    help..can you tell me the value of this capacitor?

    If your multimeter does not measure capacitance, you could measure the capacitive reactance using s 60 Hz low voltage transformer and a resistive voltage divider with your multimeter. A 165 pF capacitor has 16 MΩ reactance at 60 Hz. A 1650 pF capacitor has 1.6 MΩ reactance at 60 Hz. If you...
  6. hevans1944

    help..can you tell me the value of this capacitor?

    Either value is within the measuring range of common multimeters with a capacitance measuring function. Why not measure one? Images on the web lend credence to 1650 pF OR 165 pF. Umm, how much do you want for two pounds of these capacitors? Just asking. I don't have any use in mind.
  7. hevans1944

    help..can you tell me the value of this capacitor?

    Looks like a 165 picofarad dipped mica, 1% tolerance, 500 V rating.
  8. hevans1944

    Sending data via Telit GSM/GPRS module

    Maybe something on this Google search results page will help?
  9. hevans1944

    Control stepper motor with PIC, maximum output frequency of PIC

    [ @Nyein Chan what you have just done is called "hijacking a thread" and that is not good manners. Although your question is on-topic, it does not appear to have originated from the same application that @Emam is posting about... unless the two of you are co-workers on the same project. If you...
  10. hevans1944

    LC Resonance Signal Origin Detector

    Try solving the equation using scientific notation for the variables. The coil dimensions and capacitor you specified resonate at about 2.73 MHz, assuming coil inductance is about 0.339 μHy with 0.01 μFd capacitor.
  11. hevans1944

    PIC16F870 frequency counter

    We don't appreciate your cross-posting the identically same question on multiple forums at the same time, for example here. There are two solutions to your problem: either measure the period between pulses, or count the number of pulses that occur in a fixed time interval. Here is a website to...
  12. hevans1944

    LC Resonance Signal Origin Detector

    Your idea is sound in theory, but IMO totally impractical at these two frequencies.
  13. hevans1944

    Finding Correct Cable to connect Console to CRT

    It is called an RF Modulator and is obsolete since digital TV replaced NTSC analog TV transmissions. Most new TVs support both standards. Your Nintendo Gamecube produces analog NTSC video, so that is why the VCR connection works. The VCR has an RF Modulator in it that produces an NTSC analog...
  14. hevans1944

    Using a DC motor speed controller as an "off" switch?

    The device at the website you linked is a PWM controller, specified to control from 0% to 100% duty cycle at 15 kHz. The peak-to-peak output voltage of this PWM controller is constant at approximately 5 V. Only the width of the DC pulses applied to the motor changes. Your motor should not be...
  15. hevans1944

    How to detect a plug is connected to socket

    You keep alternating your use of "plug" and "socket". From your OP, the blue female connector is a PLUG and the yellow male connector is a SOCKET. Presumably, the PLUG will be energized by a contactor eventually. However, whether the contactor is energized (closed) or not, there should always be...
  16. hevans1944

    How to detect a plug is connected to socket

    Can you check for continuity between NEUTRAL and GROUND in the plug? Should be continuity when plug is mated to receptacle, no continuity when plug is disconnected from receptacle.
  17. hevans1944

    picking components for a stir plate

    Sounds like your problem is solved!
  18. hevans1944

    picking components for a stir plate

    The PWM controller listed on EBay does not work with brushless DC motors. Scroll to bottom of listing page to read vendor disclaimer. I think most small computer fans are brushless, incorporating some sort of internal electronics that apparently does not play well with either a PWM or a variable...
  19. hevans1944

    picking components for a stir plate

    This sounds like a natural application for an Arduino Uno with a PWM output driving a MOSFET which drives the fan motor. Or you could go on Ebay and find a 20 watt wirewound potentiometer with about 100 ohms or so resistance. Wire it up as a rheostat (two terminals) in series with the fan motor...
  20. hevans1944

    Level shifter

    I think you must be right. I used to use PrintKey 2000 at work, but after just installing it on my laptop, I can't get the rectangle selection tool to work.:(
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