Search results

Search Forums New Posts
  1. WHONOES

    AC 18650 Replacement?

    How is the connection from battery to LED achieved?
  2. WHONOES

    1W audio power amplifier driven by electret ?

    Maybe but, they will be related.
  3. WHONOES

    Amplifying a signal comming out from an aux port

    What access do you have to electronics components in Morocco?
  4. WHONOES

    Resistivity question help

    If I remember correctly, the 0.017μΩ meters refers to a 1 Metre cube of solid copper. Calculate from there.
  5. WHONOES

    AC 18650 Replacement?

    A simple way would be to measure the current drawn by the LED from your battery and go from there.
  6. WHONOES

    Help with diode replacement

    Does the PCB have a manufacturers name and part number on it. If so it may be possible to get some info on the board such as a schematic or Bill of Materials (BOM) which may help.
  7. WHONOES

    3-pin PC case fan -- power from alternative source?

    You are right Harald. I've just had a look on their website and as you say there is not a whole load of information available. It does seem that the fan requires just the 2 connections and current consumption is reasonable at 380mA and will start turning on as little as 5V. I suggest that Mr...
  8. WHONOES

    3-pin PC case fan -- power from alternative source?

    The fan could be using a brushless motor which is quite common these days. Normally the fan unit will have all the control circuitry built in. It sounds as if yours may indeed need some sort of pulse train on the extra lead with some sort of PWM. You could try driving it with a function...
  9. WHONOES

    Amplifying a signal comming out from an aux port

    Do you think you can build a small amplifier as a project? You will need to make a simple power supply as well. If so, we will tackle it one step at a time.
  10. WHONOES

    Amplifying a signal comming out from an aux port

    A small power amplifier seems to be all that you need. How far do your electronics skills extend?
  11. WHONOES

    Pioneer Spec 4 Amplifier part substitutions

    Have a look at the link below. It is a huge cross reference list from Motorola. It may be of some help. https://www.updatemydynaco.com/HistoricDocuments/PowerTransistorCrossReference.pdf
  12. WHONOES

    Amplifying a signal comming out from an aux port

    If as you say, you are getting 2V from your Aux output (how do you know that?) then you will need a small power amp to drive your speaker. You will need substantially more current to drive the speaker that the few milliamps that come from Aux out or another opamp.
  13. WHONOES

    Design bass amplifier

    I would (and have) used a Sallen-Key equal value component filter. It involves putting a small amount of gain round the amplifier which then controls the Q making it much easier to calculate the RC values required. Have a look in Don Lancaster's Active Filter Cookbook. I would also use the...
  14. WHONOES

    Removing DC offset

    Can't see why a divider would introduce an offset unless the tail is not at ground.
  15. WHONOES

    MOSFET Circuit Help

    Have you tried running the fan in the box in its normal position but power by an external supply?
  16. WHONOES

    Switching high currents

    Don't forget that Rds will increase as the device warms up. Your chosen device datasheet should indicate by how much.
  17. WHONOES

    Removing DC offset

    You could fairly easily offset the "offset" using an opamp. Can you give us a picture of a scope trace showing the signal and give it a ground reference using another scope trace if necessary?
  18. WHONOES

    Acceptable Zener regulator tolerances

    What is the zener type you are using? It is possible to get ±2% tolerance parts
  19. WHONOES

    Acceptable Zener regulator tolerances

    The voltage present on your zener diode depends on its published tolerance and the amount of current passing through it. ±5% is typical for many types, 5% of 27 is 1.35V so would give a voltage of 25.65V at the extreme end of its negative tolerance.
  20. WHONOES

    Switching high currents

    Re reply #4: A thyristor or SCR (they are the same thing) is not of much use for switching DC current. SCR's have a latching current, generally quite a small percentage of their carry current. Once the carry current has exceeded that, it will stay switched on regardless of what you do to the...
Top