Circuits & Schematics - Measurement - 9

A self-biasing thermistor circuit had an overall dominant thermal/ electrical time constant as small as 25 msec but had a significantly rounded response following a square (thermal) input pulse of 100 msec; the source was a pulsed blue LED. A ...

Solid-state-lighting applications are quickly moving into the mainstream. Although they are more efficient, the LEDs that produce the low-cost light often require a complicated driver circuit. Testing the driver circuit using LEDs, although easy, ...

You may lack experience and hardware when designing battery-operated products. The battery life of a product can depend more on the ESR (equivalent series resistance) than the terminal voltage. This situation is especially true when you use ...

Figure 1 is a micropower voltage-to-frequency converter. A 0 V to 5 V input produces a 0 kHz to 10 kHz output with a linearity of 0.05%. Gain drift is 80 ppm/ C. Maximum current consumption is only 90 µA, almost 30 times lower than currently ...

Analog circuits for long-term testing of passive components, such as 0.1%-tolerant resistors or high-intensity white LEDs, often require a constant current. Using two op amps and a voltage reference, you can develop a circuit that provides a ...

The standard way of using an RTD (resistance-temperature-detector) sensor is to include it in a bridge followed by a differential amplifier. The problem is that two nonlinearities one from the sensor and another from the bridge affect the transfer ...

In power supplies or battery chargers, you often need information about the current flowing in the high-side rail. Figure 1 shows a common circuit for obtaining this information. Figure 1. This method for measuring high-side supply current requires ...

Requirements for portable, short-range telemetry systems frequently include low power consumption, small size, and low cost. The circuit in Figure 1 meets these criteria and uses only three off-the-shelf ICs and a few passive components. Although ...

The article describes an RGB incident light sensor that uses colored LEDs as narrow-spectrum photosensitive elements. In the process of prototyping the RGB sensor, LEDs from the available batches were tested. However, the best results are obtained ...

The low-cost percentage-relative-humidity radio transmitter in Figure 1 operates in a cold-storage warehouse for vegetable storage at temperatures of 1 to 5 C. It is generally difficult to collect such data from a low-temperature area with high ...