| 摘要 |
A signal generator suitable for use as a source for light emitting control units for t.v. remote control is based upon a switched oscillator gated to minimise the power drain on the supply battery. The battery (20) is coupled over a single pole switch (21) to an emitter follower amplier (22), the base of which is coupled to the light emitting diode (29). A feedback stage (14) produces an output frequency of 40 KHz and consists of a transformer (33) with a resistance (31) providing isolation between the transistor and the frequency regulating elements. The secondary of the transformer is in parallel with a capacitor (34) to fix the frequency of oscillation. The transistor cycles from inhibited to saturated condition. During the 'on' period of the oscillator no energy drain is placed on the battery. |
