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  1. Alec_t

    Circuit Diagram Help Needed

    Welcome to EP! D1 clamps the emitter voltage of IC2a to ground, since it is only the forward current through the transistor which is of interest.
  2. Alec_t

    Class problem help (Converter U-I)

    It does nothing useful if V1 stays at 5V. It would prevent the transistor base-emitter junction being driven beyond its reverse voltage rating if V1 were negative.
  3. Alec_t

    555 RC voltage rating

    Welcome to EP! Sorry to burst your bubble, but I think you'll be disappointed if you try to use a 555 to generate those frequencies. You seem to be expecting a tolerance better than 1%, but what tolerance is actually acceptable? If you check the datasheet for the 555 you will see that both the...
  4. Alec_t

    Sunn Beta Lead Guitar Amp Repair

    Have you checked for DC on any of the outputs?
  5. Alec_t

    Sunn Beta Lead Guitar Amp Repair

    I haven't analysed the circuit in detail, but I'm not surprised that you're getting cross-coupling between channels A and B. Resistors R104,5,7,8 provide a direct connection between the channel inputs. (Why??).
  6. Alec_t

    Optical Pickup

    Should be ok;) . Snag is, you'd need 12 cams in all. That's gonna weigh the guitar down somewhat :).
  7. Alec_t

    Class problem help (Converter U-I)

    Welcome to EP! If 20mA flows through R1, how much current would you expect to flow through R2 and what would be the expected voltage on the transistor collector? Are all the transistor voltages and currents within the limits specified in the transistor's datasheet?
  8. Alec_t

    5 decade old battery pack bridge

    Batteries that old are almost certainly NiCds and non-rescuable. Replace with NiMh?
  9. Alec_t

    Si826x gate driver keeps failing

    I have replied over at ETO.
  10. Alec_t

    Need your help related to this problem

    Help is what we do. We don't do your homework for you. Post your best effort so far at solving your problem.
  11. Alec_t

    You have a 1 nF capacitor

    Welcome to EP! We can point you in the right direction, but we don't do your homework for you. Post your best effort so far at doing this project.
  12. Alec_t

    4-20mA circuit and MCU

    Using an opamp for the summing (as mentioned in post #9) leads to a simple analogue implementation. Here's a sim demonstrating the principle. It uses five sensors but more can be added.
  13. Alec_t

    4-20mA circuit and MCU

    5V supply for the summing circuit will give somewhat less than 0-5V range if using a simple resistor summing network. Alternatively you could use an inverting opamp to do a linear summation.
  14. Alec_t

    4-20mA circuit and MCU

    No. The ADC input should not exceed the supply voltage of the MCU.
  15. Alec_t

    4-20mA circuit and MCU

    Here's one approach. In this simulation the sensor outputs are combined by a simple resistor network. The combined output (yellow trace) rises non-linearly as the number of sensors is increased from 1 to 24. One ADC input of the micro would be used with a look-up table to convert this combined...
  16. Alec_t

    Optical Pickup

    I don't see how an optical sensor will give a signal proportional to the string amplitude, which is what you need. As AG says, the signal will be more like a square wave and will sound awful. Or perhaps that's what you're aiming for? Built-in fuzz? :D
  17. Alec_t

    BLDC Torque

    We have no idea what your program is :rolleyes:. Are you trying to control a motor or design one? :confused:
  18. Alec_t

    I Want To Make Device To Run Pendrive On Tv

    I'm with Dave on this. What data do you have on the pendrive that you want to display? Does the TV have inputs intended for that type of data?
  19. Alec_t

    BLDC Torque

    Torque is proportional to current; so increase the current (without frying the motor :)).
  20. Alec_t

    Fan speed control

    Which version/package of the LM317T, and what size heatsink are you using? The IC may be going into thermal shutdown.
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