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  1. Rleo6965

    555 voltage controlled oscillator question

    Please read the datasheet of NE555. NE555 have have 2 comparators and 3 voltage resistor. Voltage control pin5 was connected to comparator with 2/3 reference voltage. Your 0-5V was not enough amplitude for 2/3 VCC of NE555. That's the reason that it does not affect frequency of NE555.
  2. Rleo6965

    PCB track width and high current with Mosfets

    Did you also consider placing a heatsink on FET? PCB trace might survive the high current but the FET might not.
  3. Rleo6965

    What happens when an AC powered floor-fan dies?

    PC have some small fans for ventilation of its critical components and no need for household fan. We only used household fan. When using our PC because we can't withstand 37° C here in Philippines. Your concern therefore was to see that all your PC fans were working properly and cpu heatsink...
  4. Rleo6965

    What happens when an AC powered floor-fan dies?

    Household fan bushing should lubricated every 3 months. Use engine oil or sewing machine oil. You can use WD40 to removed dried and dirty oil. But still need oil for lubrication. WD40 will only last a week and dried up.
  5. Rleo6965

    Digital programmable CDI ignition for 2-stroke engines

    You might want to consider non programmable dc cdi circuit for your motorcycle. You can just start buying needed parts and play on it. No programming required. There are so many schematics in internet. Try this one. http://mastercircuits.blogspot.com/p/cdi-schematic.html
  6. Rleo6965

    ESR TEST EQUIPMENT

    If you want cheaper. Build one. You can use old psu transformer . This ESR meter help me in faster repair in electronics. http://ludens.cl/Electron/esr/esr.html
  7. Rleo6965

    PWM output mirror??

    Use the Triggering Function of your Oscilloscope to have steady displayed waveform.
  8. Rleo6965

    Problem in a circuit?

    Your lucky. You still have 1 functioning unit for resistance test comparison.
  9. Rleo6965

    Inductance meter adapter for a DMM

    Try to shorten wire of test probe for better accuracy. Maybe solder the test clip directly to pcb. Also keep your Inductance meter from fluorescent or magnetic inducing devices. I have encountered this problem before.
  10. Rleo6965

    Potentiometer Burnout

    Basing on your circuit. 10k should not be burnout unless its center tap was connected to low resistance to ground or connected to higher dc voltage source.
  11. Rleo6965

    ATX power supply to bench lab supply? help

    You can't use -12V and +12V to get +24V and its also low ampere. Kiwi have a better suggestion that you buy that DC to DC Converter and you connect it to the +12V with High Ampere capacity ( Yellow Wire )...
  12. Rleo6965

    Problems with SMPS with TL494, again :)

    Iron powder core was not suitable for high frequency voltages. Iron powder cores mostly use in noise filter inductor. Use ferrite core for your GDT.
  13. Rleo6965

    ATX power supply to bench lab supply? help

    I'm also in the process of building Lab Bench Power Supply from 300W ATX PSU. I'm going to use it for my Car Electronic projects that the reason I have to modify the PSU circuit to have dc output of +13.8V. I also include the the ATX dc out +3.3V, -12V & +12V for Opamp Supply. Planning to have...
  14. Rleo6965

    Is anyone using DesignSpark PCB?

    The reason that some library components not found was due to improper configuration of library folders. And there' were 3 types of library of DesignSpark ie. schematic symbols, pcb symbols and components. This is to simplify creating of new components. You can add library folders from different...
  15. Rleo6965

    shielded cable helpful here?

    I agree with Dave. Some Switching Power Supply have 22khz. Possible that frequency have varied to near audible frequency range due to charging load current. Do you still hear noise when the Battery Pack was almost fully charge? Does Battery Pack have a Metal Ground Screw connection to be...
  16. Rleo6965

    do i have to resize my pics?

    I use Microsoft Office Picture Manager to resize picture.
  17. Rleo6965

    Relay configure trouble

    I hope this will help you. Pressing push button NO SW1 will energize relay and turn on DC motor. Pressing push button NC SW2 will turn off DC motor.
  18. Rleo6965

    Want to on and off solanoid valve using MOSFET

    It's still can be shorted. Semiconductor was not perfect component.:)
  19. Rleo6965

    Want to on and off solanoid valve using MOSFET

    It's only a precautionary measure in case R2 was lower value and and if short happens between Mosfet Drain and Gate. Drain voltage will therefore pass the R2 and if current was too high for PIC. PIC will be damage. For experiment circuit or personal use it's better to insert buffer ic because...
  20. Rleo6965

    Schematic from PCB drawing

    Before I use paper and pencil to draw the schematic diagram while tracing the pcb. Now , I use schematic drawing software . It's easier to draw lines , edit and drag components to its proper place for easier analysis. I use DesignSparkPCB5 software. You can use simpler schematic drawing...
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