Search results

Search Forums New Posts
  1. Audioguru

    HOW TO ID-- A 12 VOLT ZENER DIODE --ONE WATT --

    I think your TIP122 with a zener diode connected to its middle leg (its collector) and ground applies the entire input power supply to the zener diode to burn it out. I found a charger using a TIP122 and a 12V zener diode. The circuit voltages are wrong so it will not work and I show why your...
  2. Audioguru

    Need some advice my Li ion powered, pwm dimmed led light circuit please!!

    If you try to charge the battery while the battery is powering the LEDs then the charger will not know how much if any power is going into the battery then the battery might not charge.
  3. Audioguru

    Noob needs help building a circuit board

    The voltage is very important. If it is too low then the sound level from the speakers will be low or very distorted. If the voltage is too high then the pcb amplifier circuit will blow up.
  4. Audioguru

    Power adapter voltage drop/load

    You should look in Google or read the datasheets. An ICL7660 is not a voltage regulator. It and the LT1054 generate a negative voltage with an oscillator based circuit that creates a lot of noise frequency that might show on the 'scope.
  5. Audioguru

    IC problem

    I think you destroyed the IC by connecting its power supply backwards.
  6. Audioguru

    Cd4033 - 555 timer frequency counter..

    Simply look at the datasheet of the 555 and order and connect the supply bypass capacitors that are recommended. The old project in the Electronics For You website is from India.
  7. Audioguru

    What can I replace a 6v 4a AC adapter with?

    An electronic product usually must be powered from the voltage it was designed to use then it will take only as much current as it needs. A car battery can provide hundreds of Amps to a cold starter motor in winter but the clock in the car using the same very powerful battery takes only about...
  8. Audioguru

    Ltc 3780- 12v 10 amp input

    The 12V/10A power supply has a power of 12V x 10A= 120W. Then the maximum output of the buck/boost module will be a little less. But the module uses the LTC3780 controller IC plus many other parts that produce power and we do not know what is the maximum output power of the module. If the module...
  9. Audioguru

    Cd4033 - 555 timer frequency counter..

    The old 555 ICs draw a 400mA spike from the supply each time they switch. Therefore the datasheet spells out two very important supply bypass capacitors that are missing in this bad circuit. I think Cmos 555s should be used.
  10. Audioguru

    How Can I Bypass This Timer?

    You need a heater or heating blanket that has temperature regulation.
  11. Audioguru

    Modifying AGC circuit

    I am surprised that the LM358 worked well because it produces awful crossover distortion and hiss, and has poor high frequency response.
  12. Audioguru

    Using an N-Channel MOSFET instead of an NPN transistor reduces main circuit voltage

    In the datasheet of the Mosfet read what the drain-source current is at the gate threshold voltage. Almost nothing!. It is the threshold of it beginning to conduct so it is almost turned off. The threshold voltage has a range so some Mosfets need a much higher gate voltage to barely turn on...
  13. Audioguru

    Inverter Theory

    A 6kW inverter is not perfect, it gets hot. It takes additional battery power to produce that heat, maybe another 1.5kW so the maximum battery current will be 7.5kW/12V= 625A! What 12V battery will supply 625A continuously without boiling? A bus full of paralleled 12V batteries? Many home...
  14. Audioguru

    Powering my IC

    The datasheet for the SN74HCT00 says that its absolute maximum allowed output current is 25mA then 30mA in an LED will probably destroy the IC and the LED. Most ordinary LEDs are spec'd and used at 20mA. When the supply voltage is 5V then the maximum allowed input voltage is a little more than...
  15. Audioguru

    Powering my IC

    The 74HCT00 is designed to be very fast (the H in its numbers means High speed) and to be compatible with 40 years old TTL logic (the T in its numbers). If it is connected wrongly then its high output current can destroy it. Since you have a 9V battery for the power supply then you should use a...
  16. Audioguru

    Power output from a mobile phone aux socket

    32 ohms earbuds are very loud at 0.1W. Then the voltage is 1.8V RMS. The power of 1.8V RMS into an 8 ohm speaker is 0.4W if the current is not too high. The current of 1.8V RMS into 32 ohms is 56mA. 56mA into an 8 ohm speaker is almost nothing at 0.025W. If you hold large 8 ohm speakers directly...
  17. Audioguru

    EEG Question on Getting Data to Computer

    The "safety jack" does not prevent electrocution, it prevents strangulation. The very low output level of an electrode must be amplified by a battery-powered preamp to a level high enough to feed an opto-coupler.
  18. Audioguru

    EEG Question on Getting Data to Computer

    The signal at the probes is very small. It must have a battery-powered preamp to raise it high enough to drive an isolator.
  19. Audioguru

    EEG Question on Getting Data to Computer

    Instructables have many errors. There is a horrible electronic one one with LEDs that has been copied many times and the author said he is 10 years old. Yes, any electrical medical device MUST be isolated to prevent electrocution of the patient if the wiring goes is faulty.
  20. Audioguru

    Aerial (roof) rotating antenna operation?

    Then throw it away and buy a new antenna rotator.
Top