| 摘要 |
<p>The present invention provides a testable precision variable gain current-to-voltage amplifier apparatus which includes an op amp (15) and has a test mode of operation wherein the gain is independent of the gain of the amplifier when operated in the normal amplification mode. The invention enables a test signal, preferably a test voltage (Vt), to be injected into the amplifier circuit to test the functioning of the op amp (15) and thus the amplifier. Because the gain of the amplifier in the test mode is independent of the gain of the amplifier when in the normal mode, a simple and easy method of checking the functioning of the op amp is provided which does not require knowing the gain of the amplifier and then selecting the proper test input to use.</p> |
