An electronic apparatus comprising: a communication interface configured to communicate with an external device, wherein the external device includes a time domain reflectometer device; a memory; and a processor, wherein the processor is configured to: transmit a control signal to the external device requesting the external device to apply a first signal to a transparent electrode sheet for a touch panel, the transparent electrode sheet being connected to the external device, receive, from the external device, a first point at which the first signal is applied to the transparent electrode sheet, a second point at which a second signal that is a response signal to the first signal is acquired by the external device, and a waveform of the second signal, and identify whether a defect exists in the transparent electrode sheet based on a difference between the first point and the second point, and the waveform of the second signal, characterised in that: based on the difference between the first point and the second point being less than a predetermined time and a voltage magnitude of the second signal being less than a predetermined value, the processor is configured to identify that at least two of a plurality of lines included in the transparent electrode sheet are shorted to each other or at least some of the plurality of lines are shorted to a ground. a communication interface configured to communicate with an external device, wherein the external device includes a time domain reflectometer device; a memory; and a processor, wherein the processor is configured to: transmit a control signal to the external device requesting the external device to apply a first signal to a transparent electrode sheet for a touch panel, the transparent electrode sheet being connected to the external device, receive, from the external device, a first point at which the first signal is applied to the transparent electrode sheet, a second point at which a second signal that is a response signal to the first signal is acquired by the external device, and a waveform of the second signal, and identify whether a defect exists in the transparent electrode sheet based on a difference between the first point and the second point, and the waveform of the second signal, characterised in that: based on the difference between the first point and the second point being less than a predetermined time and a voltage magnitude of the second signal being less than a predetermined value, the processor is configured to identify that at least two of a plurality of lines included in the transparent electrode sheet are shorted to each other or at least some of the plurality of lines are shorted to a ground. transmit a control signal to the external device requesting the external device to apply a first signal to a transparent electrode sheet for a touch panel, the transparent electrode sheet being connected to the external device, receive, from the external device, a first point at which the first signal is applied to the transparent electrode sheet, a second point at which a second signal that is a response signal to the first signal is acquired by the external device, and a waveform of the second signal, and identify whether a defect exists in the transparent electrode sheet based on a difference between the first point and the second point, and the waveform of the second signal, characterised in that: based on the difference between the first point and the second point being less than a predetermined time and a voltage magnitude of the second signal being less than a predetermined value, the processor is configured to identify that at least two of a plurality of lines included in the transparent electrode sheet are shorted to each other or at least some of the plurality of lines are shorted to a ground.