Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 277

Circuit 86: The functioning principle is described on page 248.
Circuit 87: If the voltage at the emitter of T2 reaches ignition level, the unijunction transistor switches
abruptly through. C2 discharges instantly and T2 blocks on spot. C2 is slowly recharged via R4 and so it
continues.
Fig. 3.86: Circuit
86: Mosquito
repeller
Fig. 3.87: Circuit 87
– Metronome with
discreet unijunction
transistor
279