在电子学 ， 电流电压转换器（英语：Current-to-voltage converter；又称为转阻放大器，英语：transimpedance amplifier,简称TIA） 是将电流转换为电压的放大器。理想情况下，其输入阻抗为零，与输入 信号电流。它的输出可能有低阻抗，或在高频率的应用，可驱动传输线匹配;输出信号的电压测量。

因为输出电压和输入电流、增益，或输出到输入的比率，以欧姆为单位表示。

当构建一个简单的运算放大器电路（右），增益等于负反馈电阻。

转阻放大器通常用在光纤通信，功能在将光电流转换为电压信号。

In electronics, a transimpedance amplifier (TIA) is a current-to-voltage converter, most often implemented using an operational amplifier. The TIA can be used to amplify the current output of Geiger–Müller tubes, photo multiplier tubes, accelerometers, photo detectors and other types of sensors to a usable voltage. Current-to-voltage converters are used with sensors that have a current response that is more linear than the voltage response. This is the case with photodiodes where it is not uncommon for the current response to have better than 1% linearity over a wide range of light input. The transimpedance amplifier presents a low impedance to the photodiode and isolates it from the output voltage of the operational amplifier. In its simplest form a transimpedance amplifier has just a large valued feedback resistor, R_f. The gain of the amplifer is set by this resistor and because the amplifier is in an inverting configuration, has a value of −R_f. There are several different configurations of transimpedance amplifiers, each suited to a particular application. The one factor they all have in common is the requirement to convert the low-level current of a sensor to a voltage. The gain, bandwidth, as well as current and voltage offsets change with different types of sensors, requiring different configurations of transimpedance amplifiers.