Front end development is crucial in optical tomography. It gives the first impression on how reliable the tomography system towards its measurement. Therefore, transmitter and receiver circuit must be developed carefully with good analysis for each selection of the component units. This paper will show the effect of circuit development towards linearity performance. The aim of this paper is to construct a transmitter and receiver circuit for optical tomography application. This is done by capturing a voltage unit at the receiver side in response to the existence of obstacle that interrupt the light path between transmitter and receiver. The experiment design uses a same type of obstacle with different sizes between 0.5 until 3mm. From the result it shows the bigger the object the voltage loss value also increasing. This shows a linear relation between both parameters.