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It can measure up to V DC input. The input measuring signal is analog voltage. It does not mean that we can only use it to measure dc voltage. We can use another analog sensor such as analog type temperature sensor LM35 to measure temperature or analog type current sensor to measure electrical current. The diagram below shows the pin configuration of ICL with two types of packages.
Circuit design I create the package for this IC by myself. This module is designed to measure a DC voltage up to V with polarity. The schematic below show the full design of this project. Power supply section As mention in the previous section this IC could operate in two modes. So we need some power converter block to get this mode. However the circuit is more complex and we will not cover its operation here.
It can drive the SSD directly without any resistors. The SSD are individual digit and common anode type. In this project I use 0. I added some resistors to each common of digit to decrease the current flow through thus decreasing the brightness of all segments. Reference capacitor This capacitor C1 help the system from rollover error. Integrating resistor Integrating resistor R3 is used for buffer amplifier and integrator.
We must select it carefully. If the module is design to read analog value three times per second the value of CINT must be 0. When we use mV scale the C-AZ must be 0. In the case of 2V scale it must be 0. It will generate the oscillator of frequency: The period is : The conversion cycle is: Since the conversion takes ms.
So it generate the output of analog input voltage 3 times per second. Voltage reference and display count The voltage reference is use for reference voltage for ADC. Reference voltage effect the output. The input voltage is the signal to be measure by the module.
As usual it can measure 2V maximum. We use voltage divider to scale the measuring voltage down. In this case we scale it to We have the relation of this circuit below. Completed module and Gallery I attached the design file here.
Quick C: PIC16F818