ABSTRACT
This chapter covers voltage buffer amplifier design. A good voltage buffer amplifier should have the following properties: (i) high input impedance, (ii) low output impedance, (iii) close to unity voltage gain, and (iv) wide bandwidth. Most voltage buffer amplifiers discussed in this chapter easily meet these requirements. Specifically, the input impedance is greater than 100kΩ. Output impedance is lower than 200Ω for vacuum tube voltage buffer amplifiers and much lower output impedance for solid-state semiconductor voltage buffer amplifiers. Bandwidth is greater than several hundred kHz and many of the voltage buffer amplifiers go beyond MHz range. Vacuum tube buffer amplifiers are first discussed, followed by buffer amplifiers implemented by hybrid, op-amp, and discrete components. A high current buffer amplifier, which is capable of delivering over 15A of current, is also discussed. Finally, some practical applications for buffer amplifiers are illustrated.
