Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 306

Circuit 154 to 156: The electrolytic capacitor C2 and R5 together form a phase shifter. A phase-shifted signal
is thus shifted from the output (collector T1) to the input (emitter T1). There the original signal is mixed in,
creating the typical phaser sound effect.
308
Fig. 3.155: Circuit 155 – NF
phase shifter 90°
Fig. 3.156: Circuit 156: LF
phase shifter 180°