Ceramic electrically tunable capacitor - has electrode and ceramic laminated interleaved with conducting control electrode

摘要

The ceramic electrically tunable capacitor maintains the tuned value after switch off of the equipment. When manufactured, the capacitor has a definite long term value but can be electrically tuned back to another value over a certain range, this value can also be held during non-operational conditions. The capacitor is formed of several laminates (22-31) of ceramic material and between each laminate is an electrode layer (1-11). Alternate odd electrode layers (1,5,9) are connected to one (A) of the capacitor terminals and the other alternate odd layers (3,7,11) are connected to the other capacitor terminal (B) to form the complete capacitor. The even layers (2,4,6,8,10) which interleave are the control electrodes connected to a control terminal (C). The electrical potential applied to the control electrodes uses the ferro-electrical hysteresis properties of the ceramic to adjust the capacitor value. A typical value capacitor could be tuned from 6.7nF to 8.3nF by the application of 50 volts.