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  1. WHONOES

    RF time of flight

    Do what they do in some radar systems. In the responding device, set a time before transmit period which remains constant regardless of what ever processing is taking place. Obviously the set period needs to be longer than any processing that takes place. Then when receiving the return that...
  2. WHONOES

    Create controlled 50v pulse

    Try the attached circuit. It just uses a monostable HC 123. It will produce a pulse of almost any width. R1 may be made variable so that your pulse width may be set accurately. The output stage is triggered from the inverting output of the monostable. This means that Q2 is normally on which...
  3. WHONOES

    Trying to assemble a high voltage low current PSU

    You could always try a small transformer with a diode and capacitor multiplier on the output. You could easily achieve the required O/P volts. The output current would be diminished with each stage. Have a look at the following link which explains it all...
  4. WHONOES

    Understanding, Optimization/Realization of the voltage controlled current source.

    Ta, missed that bit.
  5. WHONOES

    Understanding, Optimization/Realization of the voltage controlled current source.

    Your circuit is wrong. The load should be in the FET drain circuit whilst the source of your FET should be connected to the resistor "U CONTROL". That resistor should be a constant value and not variable. The 300Ω pot should be a fixed value and should go to the negative input of the LM324. The...
  6. WHONOES

    50w rms into 8 ohm load amplifier circuit using single dc power supply

    It always pays to design for worst case. Which should include an appreciation of the limitations of the components you hope to use. Edit: Another useful tool is the Failure Modes and Effects Analysis (FMEA) which forces you to analyse your design in minute detail and to try to predict what...
  7. WHONOES

    activate one coil in press, and the other in second press

    The good old 4013 will perform that function when configured as a divide by 2.
  8. WHONOES

    Cheap N-type MOSFET for PWM driving many LEDs with 3.3 V logic?

    If you are going to drive the FET's directly from 3.3V logic, the Fet's will not be fully enhanced and indeed may not even turn on depending on the gate threshold voltage. With the first of your suggestions, having had a look at the datasheet, it would be about 1/2 on with consequently higher on...
  9. WHONOES

    Audio amplifier to amplify a load cell signal

    ok
  10. WHONOES

    50w rms into 8 ohm load amplifier circuit using single dc power supply

    Absolutely. It always makes good sense to perform a MONTE' especially when designing a totally discreet circuit for you never know what may be lurking to catch you out. But I suspect as AG and Hevans have alluded they stick some bits together with little regard for the vagaries of the components...
  11. WHONOES

    Audio amplifier to amplify a load cell signal

    A properly implemented instrumentation amp should be capable of rejecting the common mode noise is that is what your problem is.
  12. WHONOES

    50w rms into 8 ohm load amplifier circuit using single dc power supply

    I'm sure you are right or the designer did not understand the implications of what he was doing.
  13. WHONOES

    Unable to find replacment potentiometer

    If it is a volume control then the absolute value is not that important perhaps something in the range of 10K to 20K. The control is ratio metric. If it is a tone control pot then, the value is more important.
  14. WHONOES

    SMD code required

    Follow the attached link which will take you to a downloadable SMD code book that should tell you all you want to know. https://www.sphere.bc.ca/download/smd-codebook.pdf
  15. WHONOES

    50w rms into 8 ohm load amplifier circuit using single dc power supply

    The value of R2 in the power amp above is about right. This because: at a supply of ± 35V, the tail resistors of Q1 and Q2 set the collector currents of Q1 and Q2 at about 1mA. The voltage drop across R2 with 1mA passing through it is 680mV which is just enough to turn on Q3 taking into account...
  16. WHONOES

    50w rms into 8 ohm load amplifier circuit using single dc power supply

    No problem with the design philosophy though there are some improvements that could be made but, this particular version would not be very reliable as the BC108 input transistors are only rated at 25V and on a ±35V supply would have 35V across them causing them to fail. Replacing them with...
  17. WHONOES

    Charge time for lithium batteries

    Was just pointing out how long it would take to charge the batteries if they really were 18650 mAH capacity.
  18. WHONOES

    Charge time for lithium batteries

    Bob K is correct regarding the process. Simplistically,if your Batts are really 18650mAH capacity and the charger output is a max of 130mA then a fully discharged battery will take 18650 / 130 hours to charge assuming 100% charge efficiency which is not realistic. That translates to an absolute...
  19. WHONOES

    Converting an existing amplifier into a subwoofer amp

    The amp shown in you schematic is a bog standard design for class A/B. It can be turned into a class A by simply cranking up the current in the output stage. This is done by adjusting the values around the Vbe multiplier of Q6 R11 and R12. There are improvements that could be made to the...
  20. WHONOES

    CTEK MXS 3.8 repair

    That's good.
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