Public info about the author: MicroCapDesigner

  • With this compensation circuit, the gain measured on dB(V(Vout1)) is equal to -Gfc (e.g. + 6 dB here) at the selected crossover frequency fc (3 kHz in this SPICE simulation).

    • 6dB at 3khz
  • Transistors level SPICE model of high gain and wideband amplifier RCA4030. This device achieves a gain of 37dB and a bandwidth of 55 Mhz. The emitter follower input and output stages provide a 150 KOhm input impedance and a low output impedance for coupling to other circuits. Typical applications are in video and IF amplification, modulation, mixers, etc.

    • AC analysis
  • the Gummel Poon model represents a more detailed modeling of the bipolar junction transistor than the Ebers-Moll model. In this model is taken into account the non-linearity of the currents beta ratio of the transistor.

    • non linear beta vs log collector current collector and base log current vs vbe
  • This simple circuit shows how to locate the pole of the optocoupler model, calculating the pole added by the capacitor Cpole= 1/(6.28*Fp*Rpullup), where Fp is the bandwidth of the collector voltage. In this SPICE simulation Cpole is 2.2nF and Fp is 3500hz.

    • AC analysis -3db at 3500hz
  • SPICE simulation of a low noise balanced microphone preamplifier, the input stage consists of differential pairs of transistors 2N4403 and BC549, a common mode gain control connects the emitters of the pairs. A differential operational amplifier implemented with a TL071 provides a balanced to unbalanced buffer because the circuit is differential in and out.

    • gain and phase vs frequency analysis transient analysis and total harmonic distortion