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  1. WHONOES

    Speaker/s project - for amplifier.

    You will get feedback from a two speaker system, it doesn't have to be a point source The addition of a tweeter will make your system sound sharper.
  2. WHONOES

    Speaker/s project - for amplifier.

    I use a tweeter in my guitar speaker and amp, all home brewed. I use 2 X 10" Celestions along with a dynamic horn tweeter. I get exactly the sound that I want from my Strat.
  3. WHONOES

    class A push - pull amplifier ?

    No more interest in post due to posters attitude.
  4. WHONOES

    Using spice in EAGLE

    Again, try Simetrix you can download a free version. I have been using it for many years. See link below. Download Free Demo - SIMetrix/SIMPLIS Elements
  5. WHONOES

    class A push - pull amplifier ?

    Class B has no quiescent current flowing in the output stage and leads to crossover distortion. The small current in class AB output stage ensures that crossover distortion is kept to a minimum. Class A as previously mentioned has a large current flowing in the output stage proving superior...
  6. WHONOES

    class A push - pull amplifier ?

    Class AB transistor amplifiers are always biased to the mid point otherwise they would not work correctly. Class A transistor amps are just class B (or AB) biased to have a large current flowing in the output stage in the quiescent state. A class AB would have the same output stage topology but...
  7. WHONOES

    class A push - pull amplifier ?

    Class A can also be push / pull. Heat is generated in the majority of circuits, it just depends on the level. It is a by product of power being consumed.
  8. WHONOES

    class A push - pull amplifier ?

    Try Simetrix. It's very good.
  9. WHONOES

    class A push - pull amplifier ?

    What do you want to use your creation for. The link you provided seems to be for r.f. amplifiers.
  10. WHONOES

    What is the principle of swipe card to unlock?

    Why do you want to read swipe card data?
  11. WHONOES

    Can BC548 be replaced by 2N3906 and 2N3904?

    I think the BC prefix was initiated by Mullard.
  12. WHONOES

    Need to generate a 1kHz square wave with amplitude +12v to -12v

    See attached schematic and graph. The potentiometer has been included so that you can adjust the frequency to your exact requirements. Any questions, come back!
  13. WHONOES

    Need to generate a 1kHz square wave with amplitude +12v to -12v

    It is easy enough to put a couple of transistors on the output of the opamp to boost the current required. I'll post a circuit in a while. I will include current limiting to protect the output against a short circuit.
  14. WHONOES

    Need to generate a 1kHz square wave with amplitude +12v to -12v

    The input impedance of the good old 741 is quite low, in the order of 100K if my memory serves me correctly, which would affect any calculations. I would go for something a bit more modern like the TL series of op amps ant of the TL031, 071, 081 would fit the bill. If all you have to hand is the...
  15. WHONOES

    Just When I Thought it was Going to Be Easy

    If it has the manufacturers marking on it (I don't mean some obscure Chinese outfit) and it says it is a TL081 then I think it is safe to assume it is a TL081. Buying from Amazon is no guarantee that they are Kosher!
  16. WHONOES

    Need to generate a 1kHz square wave with amplitude +12v to -12v

    What you require can be easily achieved by using an op amp multivibrator. See the link below that explains the fundamentals. Op-amp Multivibrator or Op-amp Astable Multivibrator (electronics-tutorials.ws)
  17. WHONOES

    Just When I Thought it was Going to Be Easy

    The 4558 is indeed a dual opamp so its pinout would be the same as the TL082. It's easy to discover these things, just look up the datasheet!
  18. WHONOES

    Relay or MosFet to switch a 12V signal?

    The output of your circuit is going to experience a load of some sort. You inferred that it could be up to 200mA though most likely less. That is all R1 represents and is not meant to be absolute, it is just an indication of where whatever is attached to your circuit should go. The ground end of...
  19. WHONOES

    Amplified Mini Speaker Modifications

    Can you establish whether the push button switch takes the uP pin high or low.
  20. WHONOES

    Relay or MosFet to switch a 12V signal?

    No, R1 which is your load does not go through the switch, it goes directly to ground.
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