Halogen lamps driver circuit

Using electronic circuit below can be made an electronic switch for halogen lamps. Switching circuit, for low voltage halogen lamps, extends the life of these lamps as they provide increase slowly filament current.
Lamp switch T1, a MOSFET channel resistance which is only 0.08 ohms, providing low loss (<250 mW, where the prototype). Control is via modulation pulses in duration, which also tends to minimize losses.

Order on / off is given by S1. IC2b flip-flop is a circuit for clock divider by 2, IC2a. When the Q output of the divider is one lamp is lit or under priming, when output Q is 0, the lamp is off or about to be extinguished. The lamp can be automatically disconnected by IC3, after a predetermined time calculated using this formula: t = 32768 x 2.3 x R4 x C7 , where R4 is in ohms and C7 in Farads. The values in schedule, timing is 700 s (11 minutes).