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  1. Rleo6965

    Computer monitor as TV?

    I think you need a CATV converter with built-in TV Tuner for your flats creen monitor.
  2. Rleo6965

    Chronograph for bullets

    You can use 74HC series CMOS IC in replace with CDXX series. But take note that they are not pin compatible. Replace CD4001B with 74HC02 Replace CD4012B dual 4 input NAND 74HC20 or with 74HC10 Triple 3 input NAND gate. We only use 3 input pin in our diagram. Other input pin was tied to +VCC...
  3. Rleo6965

    Chronograph for bullets

    I think we don't have problem with mechanical and cmos propagation delay. As long that we use same Limit Switch for 2 sensor. I'm not very good in explaining. Hope illustration below will help. When bullet hit Start Switch. The Counter will not start counting because of mechanical delay of...
  4. Rleo6965

    IGBT ignition coil driver

    It's really hard to eliminate noise especially in +12V side of Ignition Coil due to high charging current. All we can do was to minimize noise on +5V side in PIC to avoid reset problem. Try solder 1,000 mfd 16V and 0.1 mfd in parallel with +5V etch or VDD of PIC. Can you post final circuit...
  5. Rleo6965

    Running 175ft of cat5 solid cable with 12v/5v at the end

    You can also use 1 pair for 12V and another pair of wire for 5V and use remaining 2 pair for ground wire connection. This will reduce voltage drop on wire.
  6. Rleo6965

    Chronograph for bullets

    Please see drawing. Suggestion only. Drawing of Bullet Sensor Speed for Start Sensor and Stop Sensor. Initial position of Aluminum frame will cause Normally Open contact of Limit Switch to be Closed. Same position of initial status of Start and Stop sensor switch in my proposed circuit...
  7. Rleo6965

    Chronograph for bullets

    Try this simple circuit. Draws only 2ma suitable for battery operation. There's no capacitor circuit might cause inaccuracy of timing. It's up to you to design mechanism for the start stop switch. If circuit favorable to you . I can also think of mechanism for the start stop if you want too...
  8. Rleo6965

    Car Immobilizer problem

    Use this formula for monostable. T=1.1 X R X C
  9. Rleo6965

    basic digital troubleshooting

    Have you tried using "Ext. Trigger Input" of scope to sync waveform in your scope?
  10. Rleo6965

    Car Immobilizer problem

    Ooops. It's a Power On Delay Timer circuit. Did'nt notice earlier.:D Try to use 47 ufd and 1.2Meg resistor combination for 60 seconds delay.
  11. Rleo6965

    basic digital troubleshooting

    This might help.
  12. Rleo6965

    Car Immobilizer problem

    Are you sure timer circuit was working? Pin4 Reset pin was tied to Pin2 Trigger. Your resetting the timer every time you trigger it. Tie pin4 to pin8 should be better.
  13. Rleo6965

    555 TIMER - Trigger Pin 2 Voltage??

    @enigma Almost all correct. "Very low voltage " should be below 1/3 of VCC or for 9V VCC 1/3 should be =3V. That means trigger will occur if pin2 start to pass below 3V and should be momentary and must goes up again higher than 1/3 VCC to avoid re-trigger of NE555 for monostable mode.
  14. Rleo6965

    Short on a psu LS1904006A

    If the coil was a ac line filter choke. You can use psu and monitor ac line filter choke as long that winding coil was not smaller the original choke. I have encountered a carbonized filter choke. I just removed the the defective winding and rewind it again with same size of copper and turns.
  15. Rleo6965

    555 TIMER - Trigger Pin 2 Voltage??

    Please read carefully that Harald Kapp provided http://www.sentex.ca/~mec1995/gadgets/555/555.html. Definition of Pin Function.. Your re-triggering the NE555. Try this rc trigger circuit for NE555. It's been very long time that did not use this circuit. I hope I recall it correctly..:D
  16. Rleo6965

    IGBT ignition coil driver

    Electrical noise disturbing your +5V supply. Increase your 220 mfd 25V to 1,000 mfd 25V or higher and if your using plastic casing. Temporary wrap it w/ aluminum foil and ground the shield aluminum foil to ground using alligator clip. Just to isolate problem. If this correct the problem. Use...
  17. Rleo6965

    Neep Help: Speedometer Signal Converter

    It seems you need a divide by 8 converter.
  18. Rleo6965

    UARTS ghost signal

    That's the reason I keep coming back. They have very good advice.:)
  19. Rleo6965

    Chronograph for bullets

    Can you post your bounce circuit. It's a good start to help you.
  20. Rleo6965

    Using a transistor as a relay

    @stealthRT Its better to to see the manufacturer datasheet. Always verify all continuity of your component on a solderless breadboard. Most of the time there's a loose connection and resulting intermittent problem. Once powered on. Test all voltage on important test point to identify abnormal...
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