| 摘要 |
1. Reliable low frequency tuning fork oscillator supplied with D.C. voltage, comprising substantially in cascade a differential amplifier (1, 2) operating in its saturation region when actuated, to the first input of which the output winding (9) of the said tuning fork is connected, a transistor (3) arranged as an amplifier with common emitter at the output of the said differential amplifier, the output of the said transistor (3) being connected to the control winding (12) of the said tuning fork, so as to form a back coupling by means of magnetic coupling with the said first input of the said differential amplifier, and a tank circuit (14, 15) whose inductance, connected to the collector of the said transistor (3) by means of a resistor (17), forms the primary winding (15) of a transformer, the output signal of the said oscillator being output across the secondary winding (16) of the transformer, characterised in that a first voltage regulating circuit and a second voltage regulating circuit are connected in parallel between the terminals of the D.C. voltage supply source, the said first circuit having its output terminals connected to the first input of the differential amplifier via a first voltage divider bridge (4, 5), the said second circuit having its output terminals connected to the second input of the differential amplifier via a second voltage divider bridge (6, 7, 8) and to the supply input terminals (18, earth) of the said differential amplifier in such a manner that the inopportune modification of any one of the characteristics of the said circuits results in a marked weakening of the level of the output signal of the said oscillator. |
