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  1. audioguru2

    Audiogurus opinion of inverter

    No big deal. You have ruined this project, you know. You had my well-working corrections replaced by yours that won't work. You deleted many of my replies to people and deleted many topics of circuit discussion. What is your problem??
  2. audioguru2

    Audiogurus opinion of inverter

    Hi Sarma, If the circuit is wired properly then the supply voltage to the CD4047 will be pretty stable. There have been no complaints in the forum about my corrected circuit. Just secret e-mails to somebody.
  3. audioguru2

    Audiogurus opinion of inverter

    Hi Sarma, I agree that an electrolytic supply bypass capacitor would be needed if the battery is far away. The battery has a huge amount of very low impedance capacity, like a huge capacitor. The Cmos IC would probably be destroyed by alternator spikes if the battery is being charged in a car...
  4. audioguru2

    Audiogurus opinion of inverter

    I used 0.1 ohm emitter resistors on the output transistors to help match them so the one with the highest gain doesn't "hog" all the current then fail first. Then the remaining transistors will also fail one after the other in order of their amount of gain and Vbe. Transistors all have...
  5. audioguru2

    4 watt fm transmitter

    I have never been a ham and I haven't used vacuum tubes since about 42 years ago. There are websites for "radio pirates" that use more modern designs for VHF power amplifiers. They also have much better and more modern FM "exciters".
  6. audioguru2

    50Hz when you touch Oscilloscope probe

    Mains radiation is all around you at 50Hz. The long wires and tracks on a breadboard pickup interference. Maybe the power supply is grounded or has some capacitance to ground then the circuit's wires are an antenna. With the battery then there isn't a ground so the antenna effect from the wires...
  7. audioguru2

    Stepper motor driver

    I don't see any supply bypass capacitors in your circuit. An ordinary 555 draws a current spike of 400mA when its output switches and the motors also draw a high current so maybe the supply voltage is collapsing for a moment. Then the CD4027 wouldn't work properly. Make sure the supply and...
  8. audioguru2

    4 watt fm transmitter

    It isn't a good circuit since its RF frequency drifts. It will sound lousy since it doesn't have pre-emphasis (treble boost) like radio stations. It isn't stereo. Its high output power is illegal so maybe nobody made it. The Micromitter FM transmitter project and kit is much better...
  9. audioguru2

    Infrared Remote Control

    Hi Walid, Replace the unknown MOD rx with a modern TSOP IR receiver module that is common in TVs. Look at its datasheet. Here is its sales sheet. Then tune the 555 to make 38kHz or 40kHz to match the new receiver.
  10. audioguru2

    220vac 50hz Inverter by Ferite core

  11. audioguru2

    Audiogurus opinion of inverter

    Hi Mik3ca, Each side of the output of the inverter has a three transistor darlington circuit for its high current gain. The final output transistors are paralleled to increase their max current rating. It is a 500W inverter. It isn't perfect, it is cheap so it uses common 2N3055 transistors...
  12. audioguru2

    Audiogurus opinion of inverter

    Here we go again! The original 500W inverter project didn't work because it had many errors, so Rhonn and I corrected it. The corrected circuit has been built and proven over the years! The project had the corrected schematic and the defective one for a long time until recently, but now the...
  13. audioguru2

    Audiogurus opinion of inverter

    Hi Ante, This inverter will heat with about 100W so it will try to draw 600W. That is 50A from a 12V battery. As I said before, then the output transistors will try to conduct 25A each! But their max rating is only 15A. Do you think they will blow open or they will short? If the load is only...
  14. audioguru2

    looking for "LM3915P" sound level indicator

    Hi Hekhor, National Semiconductor makes the LM3915N which is in a plastic DIL "P" case. Digikey has 1,754 of them in stock for only $2.64US each. Find out if National will send a sample to you or if Digikey can ship one to you.
  15. audioguru2

    My amp's distorting

    Pin 3 is called "Supply Voltage Ripple Rejection" and is the half-supply-voltage-reference. It needs a capacitor to reduce ripple as shown in figure 4.
  16. audioguru2

    Inverter Circuit 12V DC to 230VAC Sine Wave

    If you use the R of an RC filter as the load, then the filter is highpass not lowpass. The output of any kind of  Butterworth filter is -3dB at the cutoff frequency. So if you set the cutoff frequency at 50Hz then the output will be at half power. 1000pF if useless at 100Hz  or 200Hz. You need...
  17. audioguru2

    Some angel out there!! need help for motor speed control by pll

    The frequency setting of the lowpass filter is determined by the momentum of the motor and its load. If the motor is strong and doesn't have a load then it can accellerate much quicker than the lowpass filter and the circuit will go beserk.
  18. audioguru2

    My amp's distorting

    Your combining circuit is correct but has 100 0hm resistors for a headphone jack output. My recommended combining circuit is the same but uses 10k resistors for either a headphone jack or a line-level jack output. A line-level output is shorted by only 100 ohms. With a 9.6V supply, the amp...
  19. audioguru2

    My amp's distorting

    Then you are shorting together both outputs and maybe are causing damage to the MP3 player. You should combine the outputs with isolating resistors: 1) Connect a 10k resistor to the output of the left channel. 2) Connect another 10k resistor to the output of the right channel. 3) Join the two...
  20. audioguru2

    My amp's distorting

    You sketched an extra 224 capacitor at the amp's input. Are you shorting together both channels from your MP3 player? The short might have damaged the MP3 player. A 10k resistor from each channel would combine them together without causing damage.
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