[CIRCUIT IDEAS] Current to Voltage Converter Most of the devices require voltage as an input quantity such as a current source, a bipolar transistor, a tube, a FET transistor, etc.Only some devices have a current input such as an ammeter, a transimpedance amplifier, a Norton amplifier, etc DEEPAK GUPTA Faiz Ashraf In these cases, we connect a voltage-to-current converter before the device Current to Voltage converter are commonly used in receivers for optical communications to convert the current generated by a photo detector into a voltage signal for further amplification A simple I2V converter can be built using OPAMP741 Operational amplifiers are widely used in signal processing circuits, control circuits, and offset no instrumentation Of all analog integrated circuits, null connect the operational amplifier is the analog integrated circuit which has the most sales and is the most widely used in the widest variety of electronic -input +Vcc circuits Its input ideally has zero impedance, and the input signal is a current Its output may have low + impedance, or in high-frequency applications, may +input be matched to a driven transmission line; the output signal is measured as a voltage The pin diagram of OP-AMP 741 is In the offset -15V -Vcc schematic diagram pin & are the supply pins null Pin number &5 the offset null pins and can be ignored Pin is the inverting input and Pin is the non-inverting one Pin is the output The output Fig Pinout for the 741 op amp cannot go above +Vcc or below -Vcc When the output reaches these limits the op amp is said to be saturated Current Source Current - to - Voltage Converter The circuit diagram is A variable voltage is connected to the inverting terminal of the op-amp through a R2 = 100kΩ 1M-Ohm résistance The noninverting terminal is grounded Because no current flows into the op amp itself, the current Iin has nowhere R1 = 1MΩ to go but through the resistor R2 Iin=Vin/R1 Vout= -R2 X Iin Vout + + Iin As seen, the output voltage is proportional to the input current but of inverting nature The output 3-15V voltage can be increased by increasing the feedback resistor