Amplifying wave generator signals

Discussion in 'Analog & Mixed-Signal Design' started by kevinnas, Sep 18, 2018.

  1. Bordodynov

    Well-Known Member

    May 20, 2015
    2,101
    639
    Unfortunately, these transistors on a current of 35 mA have a low cut-off frequency and at high frequencies there will be a lower gain. It is possible to stabilize (partially) the current by putting the resistors in the sources and shunting them with ceramic capacitors. Instead of a Zener diode, I tried to use successively connected LEDs that need to be glued to the transistor (for thermal feedback), but then there is a difficulty in setting the current. This is a more competent solution, but then you have to dramatically complicate the power supply circuit of the valves. LEDs are much worse stabilizers than a zener diode. Here is my last, simple upgrade. It allows you to more smoothly change the current and reduce the harmful effects of reducing the threshold when the transistors are heated.
    Pay attention to the changes in the scheme. Resistors at the source should be non-inductive (almost).
     
  2. Bordodynov

    Well-Known Member

    May 20, 2015
    2,101
    639
    A ten-watt broadband transformer is very difficult to manufacture. It is much easier to introduce thermal feedback and complicate the scheme.
     
Loading...