| 摘要 |
A remote signaling circuit includes a piezo-electric transducer 12 providing acoustic coupling between the input oscillator stage 11 and output stage 13 of the circuit. The input circuit includes a transistor oscillator (TR1) in which a portion of the transducer 12 provides both the frequency determining element and the positive feedback loop. The output circuit can comprise a switching circuit, as shown, or a direct current power supply. A number of input and output configurations of the transducer 12 are described, and thyristor switching arrangements for the output circuit. The transducer may be of disc form with input electrodes E51, 52 at its centre and C-shaped output electrodes E53-56; the disc is supported at its centre which is a vibrational mode. <IMAGE> |
