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  1. R

    So, how many "watts" is a 9-volt battery?

    Watts are not a quantity that you can put into a battery. Wattage is a rate of energy transference. If you want to know how much energy is in a battery, don't ask for its wattage. Ratch
  2. R

    BJT Basics questions

    You need to start from ground zero. Specifically, take a course on BJT's by attending a class, self study, or online course if available. We can help you with specific questions about a particular aspect, but we are not equipped to give you a complete course on BJT's. I learned most of what I...
  3. R

    current flow?

    I think the designation is arbitrary. Why should electrons be the arbiter of what is charged to what polarity? There are charge carriers that have the opposite polarity with respect to electrons, and they have the same status as electrons do. Read the link below. Notice the point it makes...
  4. R

    diode concept question

    There is no "concept", only diode physics. Constant current is present, but the AC meter you are using is not registering it. Try using a constant current meter instead. You are starving the diodes with the 1 meg resistor in the middle circuit. In the bottom circuit, the increase to 1.0...
  5. R

    Looking for recommendation for a good soldering iron

    I have owned the 30 watt and 60 watt soldering iron from this company for over 50 years. Only replaced the tips once. Ratch https://www.americanbeautytools.com/
  6. R

    current flow?

    First of all, "current flow" is technical slang that really should not be used. One should say charge flow, or current existence, or current present. Literally, current flow means "charge flow flow", which is redundant and ridiculous. Conventional current flow should be called "mathematical...
  7. R

    Solve current when only power and resistance is given

    You can check it yourself. Does ((5.61+106.866) ^2) * 0.04 + (5.61^2 ) * 48 + (106.866^2) * 2.5198 = 30614.4 ? What is the second solution? Is RL the same as R3? Ratch
  8. R

    Solve current when only power and resistance is given

    The power supplied by the voltage source equals the power dissipated by the three resistors. Ratch
  9. R

    Solve current when only power and resistance is given

    There are three unknowns which can be solved with three equations. There are four solution sets. Only two sets are realizable. One equation sums up the power. The second equates the voltage across R2 and R3. The third equates the R3 resistance and I3 current to the power dissipated in R3...
  10. R

    AC Theory Help

    I can show you how to calculate and plot the waveforms, but I never used Falstad. Perhaps others can help you use that particular simulator. Ratch
  11. R

    need help again lrc parallel magnitude impedance

    If you are referring to your post #5, then yes, that is basically correct. I would use ----> instead of > or >> to mean "results in". The absolute value of a complex number is well defined. Do some exercises to bond your understanding of absolute value. Ratch
  12. R

    need help again lrc parallel magnitude impedance

    You are right. The magnitude of a complex expression is not the same as the complex expression itself. The magnitude of a complex expression does not contain any "j" components, only a real number. I should have emphasized that better and not used equal (=) signs to equate the third term to...
  13. R

    need help again lrc parallel magnitude impedance

    To find the absolute value of a complex number, find the positive square root of the sum of the real part squared, plus the imaginary part squared, of the numerator and denominator separately. Don't include the "j" term when you square the numbers. The third term above is the absolute value of...
  14. R

    AC Theory Help

    What do you want us to do? We cannot give you a course on how to operate the circuit simulator. Similarly, we cannot give you a course on how to use the oscilloscope. Do you have any specific questions on how to use those tools?
  15. R

    need help again lrc parallel magnitude impedance

    Just a matter of simple algebra. Ratch
  16. R

    Thevenin voltage

    Your calculations are correct. the Voc is 0.2 volts. So the source voltage has to increase to 25 volts for the zener to start conducting. After that, the voltage across the zener will be fairly constant at 5 volts. The voltage across the zener will change slightly when the 8 ohm resistor...
  17. R

    np=ni^2 in doped semiconductors

    george2525, This link starting at page 65 gives a good explanation of temperature dependence of carrier concentration. It shows that at about 100 K, the semiconductor starts to freeze out, and at about 450 K, the semiconductor becomes intrinsic no matter how much it is doped. Read that, and...
  18. R

    np=ni^2 in doped semiconductors

    georger2525 If you take a slab of N-type or P-type silicon. and measure its resistance, it will be very high. That is because the concentration of arsenic atoms in the N-type silicon is quite small, so it does not affect the conductivity of the silicon very much. Unlike a metal, which has...
  19. R

    the concept about to basic electronics.I need basic concept of subject electronics

    Electronics, whether basic or advanced, is like any other subject. It is not a "concept". It is a study of a subset of physics pertaining to electrons with respect to their behavior and applications. Ratch
  20. R

    np=ni^2 in doped semiconductors

    Good, now I know what you are talking about. You are asking if the arsenic atom can be ionized twice? Perhaps, but more likely if there is that much energy around, it will ionize another silicon atom and produce an electron-hole pair. Even if the arsenic atom ionized twice, the second time...
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