| 摘要 |
1,151,362. Whistle/hooter and controller for model railway. R. E. IRELAND. 12 Sept., 1966 [14 Sept., 1965], No. 39167/65. Heading A6S (Also in Divisions H2 and H4] A model railway system comprises a direct-current power supply connected to a track for driving a locomotive thereon and an audio frequency signal generator connected to the track to operate a sound reproducing device electrically coupled to the track and mounted in a vehicle running thereon. The sound reproducing device is preferably coupled to the track through isolating capacitors and may be a balanced armature microphone. The motor power may be supplied through a transistor amplifier control system as shown in Fig. 3. A DC supply is connected across 31 and 32, on AC supply between 49 and 32, the tone generator output (using the same DC supply) at X and track is connected to 11 and 12. The six position ganged switch SI, S1A is used to simulate various running conditions. In the first position (as shown) capacitor 38 charges to a voltage determined by potentiometer 33, an increasing voltage with a superposed alternating component being supplied to the track via the direct coupled amplifier TR3, TR4, TRS to accelerate an engine and overcome starting friction. In position 2 the capacitor 38 discharges slowly through resistors 46 and the load, simulating coasting. In positions 3, 4 and 5 the capacitor 38 is shunted by successively decreasing resistances producing a braking effect. In position 6 the train is controlled by potentiometer 44 and the signal comprising DC with a larger superposed AC component than in position 1 gives accurate control for shunting. The tone circuit is an asymmetric astable multivibrator with alternative coupling capacitors so that the frequency spectrum of a steam whistle or diesel hooter can be produced. |
