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  1. audioguru2

    Choosing Loud Speaker

    Hi Shahriar, Everybody has a different definition of "high quality" sound. Some people have "tin" ears and can't hear low frequencies or can't hear high frequencies of can't hear distortion. Usually these people are not musical or are not interested in music. Other people hear everything and...
  2. audioguru2

    Potentiometer link to linear actuator (update)

    A "servo" used in a model airplane, model car or model boat has a motor driving an actuator and a potentiometer is linked inside for physical/electrical feedback about its position.
  3. audioguru2

    Opamp for video component buffer

    Hi Shahriar, Thanks for the article. But it is for low quality black and white video for a TV. Wellington needs a swicher for high quality colour for a computer monitor.
  4. audioguru2

    led sequencing project... HELP !!!

    A turn signal for a motorcycle needs very high power and wide angle LEDs and a high power circuit to drive them. An LM3915 drives ordinary LEDs with fairly low power. Each of its outputs would need a power transistor added to drive a high power LED.
  5. audioguru2

    led sequencing project... HELP !!!

    Hi Mark, Welcome to our forum. ;D A 4017 would light one LED at a time. An LM3915 logarithmic voltmeter world be able to do what you want if it is set for the bar mode as it indicates the exponential rising voltage of a capacitor charged by a resistor. It has outputs for up to 10 LEDs. 
  6. audioguru2

    transistor saturation

    Hi Walid, The power dissipation is max when the transistor is a linear amplifier. If it has 20V across it and only 31.25mA, or 30V and only 20.8mA then it dissipates its max heat of 625mW. When the transistor is saturated then the voltage across it is very low so it doesn't get hot. The...
  7. audioguru2

    IC 555 instead of IC 50240

    Hi RF, I realise now the PLL circuit produces a chord with only C, G and C without the E. If you want a complete major or minor chord or any other kind of chord then more PLL circuits are needed. Have you considered allowing the PLL to listen to the harp then track its frequency? Do you sing...
  8. audioguru2

    Automatic Light System

    Hi Azza, My compact fluorescent light bulbs save me money on electricity and I turn them off when they aren't needed. Soon I will get "a smart meter" so I can save money by using high power appliances during "off peak" times when electricity costs much less. My home here in Canada is heated...
  9. audioguru2

    12v amplifier?

    Hi Sasi, The TDA7240 is better than the TDA2005 even though the spec's are about the same because the TDA7240 has less number of pins and has a pcb layout in the datasheet. Thanks for the big long list of TDA amplifier ICs. I noticed that it missed out the TDA2005. I notice that most of these...
  10. audioguru2

    Opamp for video component buffer

    The opamp has a typical input impedance of 100k ohms in parallel with only 2pF. So the series 450 ohms resistance of three CD4053 switches won't cause any measurable loss.
  11. audioguru2

    Help for Guitar Control

    If the crackling problem is caused by the inputs of the TL062 opamps being overloaded then playing the guitar softly, using an 18V supply for them or using the other opamps I have listed will fix it. The 22k resistors charge the 100uF capacitor in 1.1 seconds which should be quick enough. Does...
  12. audioguru2

    Opamp for video component buffer

    Where is the loss in the video signals? The video source is made to produce a certain level of video in the 75 ohm input of your switching circuit. The CD4053 has a switched-on internal resistance of only about 150 ohms and it feeds the 1M or higher input impedance of the video amplifier so the...
  13. audioguru2

    Opamp for video component buffer

    Hi Wellington, Your inputs and outputs are L channel audio, R channel audio and video. Your monitor has RGB inputs, not just a single composite video wire. I hope the video standards for the signals of your sources and monitor are all the same. There are many different types of video signals...
  14. audioguru2

    Question about this Loud Speaker

    The Linkwitz-Riley crossover network design has been an audio standard for about 20 years.
  15. audioguru2

    Opamp for video component buffer

    The CD4053 is three two-position switches. It doesn't need a CD4017 10-steps sequencer. An alternate-action circuit can toggle all three switches with a single pushbutton:
  16. audioguru2

    "ACTIVE SUB-WOOFER AND CONTROLLER"

    Confusing, isn't it? There are capacitors near the inputs and maybe one is near the output in the picture. Then the remaining missing two capacitors are bypassing the supplies. Connect the negative wires of two 10uF polarized capacitors together. The series combination makes a 9.4uF...
  17. audioguru2

    Opamp for video component buffer

    Hi Wellington, An opamp can't drive a load that is lower than about 1k ohms. A video amplifier is designed to drive a 75 ohm video coax cable. To avoid reflections of the signal in the cable then the output impedance of the video amplifier must match the impedance of the cable and the input...
  18. audioguru2

    Question about this Loud Speaker

    Hi Shahriar, I don't know why the woofer has the round thing around it. To produce deep bass frequencies the round thing must have its rear open and the entire cabinet must be the woofer's enclosure (not just the round thing which is too small for deep bass) and either the cabinet must have its...
  19. audioguru2

    Opamp for video component buffer

    Hi Wellington, A TL072 is an audio opamp. A video amplifier IC has a frequency response that is 300 times or more higher. A video amplifier has a gain of 2 and a high current output so it can drive 75 ohm cables that are terminated with the 75 ohms input impedance of the monitor. Look for Video...
  20. audioguru2

    IC 555 instead of IC 50240

    Hi RF, A major chord is C,E, G and C for example. A minor chord is C, E flat, G and C. Then there are other kinds of chords. C, F, A and C sounds nice but I can't remember what the chord is called. The phase-locked-loop circuit you found can "follow" the root key "C" in this example and will...
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