The performance of LDRs can be influenced by ambient temperature, although the effect is not as pronounced as in thermistors. As the temperature increases, the number of thermally generated charge carriers in the semiconductor material of the LDR increases. This rise in charge carriers can lead to a decrease in resistance even without a change in light intensity. In high-temperature environments, this can result in a lower-than-expected resistance, potentially causing the LDR to inaccurately sense light levels. In precision applications, it is important to consider the temperature dependence of LDRs and, if necessary, compensate for it in the circuit design or calibration.

NTC thermistors are generally preferred in temperature sensing applications because of their high sensitivity and predictable, exponential decrease in resistance with increasing temperature. This sharp change in resistance for small temperature variations allows for precise temperature measurement and monitoring. NTC thermistors can detect minute changes in temperature, making them highly effective in applications requiring detailed temperature control and monitoring, such as in medical thermometers, environmental monitoring, and electronic devices. Their predictable resistance-temperature relationship also simplifies the circuit design and calibration process. In contrast, PTC thermistors are more often used in applications requiring over-temperature protection rather than precise temperature measurement.

Self-heating is a significant factor affecting the accuracy of thermistors in a circuit. It occurs when current passing through the thermistor generates heat, which raises the temperature of the thermistor above the ambient temperature. This increase in temperature can lead to a change in resistance that is not due to the external temperature changes the thermistor is meant to measure. This phenomenon is particularly noticeable in precision temperature measurement applications, where even small inaccuracies can be critical. To minimise the effects of self-heating, thermistors are often operated at low currents, and circuit designs may include measures to dissipate heat or compensate for the temperature rise caused by self-heating.

LDRs are not typically suited for high-speed electronic circuits due to their relatively slow response time. This slow response is due to the time taken for charge carriers to increase in the semiconductor material when exposed to light, and for these carriers to recombine when the light source is removed. This delay can range from milliseconds to several seconds, depending on the LDR’s material and construction. In high-speed circuits, where rapid response to light changes is essential, this delay can lead to performance issues. For such applications, photodiodes or phototransistors, which have much faster response times, are usually preferred over LDRs.

The spectral response of an LDR refers to its sensitivity to different wavelengths of light. Typically, LDRs have varying degrees of sensitivity across the light spectrum, with a peak sensitivity often in the visible to near-infrared range. This characteristic dictates their performance in different lighting conditions. For instance, an LDR with peak sensitivity in the visible spectrum is more responsive to daylight and is suitable for applications like automatic streetlights or daylight sensors. Conversely, an LDR with sensitivity skewed towards the infrared range is better suited for detecting IR radiation, making it useful in remote control receivers or fire detection systems. The choice of LDR based on its spectral response is crucial for optimal performance in specific applications.