Here is the simple virtual ground circuit based on discrete components. This simple design comes from miniaturization guru Sijosae. Is to make a buffer from generic discrete components. The transistors can be most any complementary pair of small-signal transistors. Suitable alternatives are the PN2222A and PN2907A. The diodes are generic small-signal types. An acceptable alternative is the 1N914. This circuit has better performance than a simple resistive divider virtual ground, and the parts cost is lower than for any other circuit mentioned here. It is, however, the least accurate of the buffered virtual ground circuits.
Circuit diagram:
Parts:
- R1,R2 = 4.7K
- R3,R4 = 4.7R
- C1,C2 = 470uF-25V
- C3,C4 = 47uF-25V
- D1,D2 = 1N4148
- Q1 = 2SC1384
- Q2 = 2SA684
- B1 = Battery