| 摘要 |
<p>The selfadjustable capacity level switch includes a high-frequency transformer (26), whose terminals of the primary winding (pw) are connected to the opposite plate (op) and the common terminal of the first and second resistor (241, 242), whose other terminals are connected to the output or the non-inverting input of the operating amplifier (1). At the same time the terminals of the secondary winding (sw) are connected to the opposite plate (o) and the adjusting plate (ap), so that the voltage on the adjusting plate (ap) follows the operational amplifier (1) output voltage. The inverting input of the operational amplifier (1) is via an adjustable condenser (32) connected to the opposite plate (op). The selfadjustable capacity level switch is almost non-susceptible to deposits which accumulate on its sensor, so that it's not required to clean the sensors during the operation of the level switch.</p> |
