Hello Everyone,
It has been quite sometime since our last visit to the blog. Well the excuse would still be the same, we are busy with Secret X Project. Well the commercial project we are attacking at the moment requires the use of DVM to display voltages and also polarity.
PIC Microcontroller would be a good option but then to simply display voltage a microcontroller will be an overkill or under-utilized.
Hence, we choose a popular IC used in multimeters for a very long time. IC7107 is manufactured by Intersil and 3-1/2 Digit, LED Display, A/D Converter. It is purely dedicated to just drive 7-Segment LED Common Anode Display units and has built-in A/D Converter.
The beauty of the DVM is that it displays +/- voltages. The circuit is quite straight forward with the datasheet having the circuit and various modes of configuration. After building the DVM, the Reference Voltage has to be set to Calibrate the DVM to display the right voltage. This Calibration is achieved by setting the 10K pot. to either 100mV or 1V depending on the number of decimal places required. Also the DVM works on 5V only. The IC7660 is a voltage converter to generate -5V as negative reference in order to show us negative readings.
IC7107 Datasheet: Click Here
DVM Schematic: Click Here
Our previous post had the GPB (General Purpose Board) model. We got the PCB made to have the professional edge. Have a look at the pictures. Circuit is provided below.
We would like to provide the schematic though the datasheet has provided which has a lot of ambiguity.
It has been quite sometime since our last visit to the blog. Well the excuse would still be the same, we are busy with Secret X Project. Well the commercial project we are attacking at the moment requires the use of DVM to display voltages and also polarity.
PIC Microcontroller would be a good option but then to simply display voltage a microcontroller will be an overkill or under-utilized.
Hence, we choose a popular IC used in multimeters for a very long time. IC7107 is manufactured by Intersil and 3-1/2 Digit, LED Display, A/D Converter. It is purely dedicated to just drive 7-Segment LED Common Anode Display units and has built-in A/D Converter.
The beauty of the DVM is that it displays +/- voltages. The circuit is quite straight forward with the datasheet having the circuit and various modes of configuration. After building the DVM, the Reference Voltage has to be set to Calibrate the DVM to display the right voltage. This Calibration is achieved by setting the 10K pot. to either 100mV or 1V depending on the number of decimal places required. Also the DVM works on 5V only. The IC7660 is a voltage converter to generate -5V as negative reference in order to show us negative readings.
IC7107 Datasheet: Click Here
DVM Schematic: Click Here
Our previous post had the GPB (General Purpose Board) model. We got the PCB made to have the professional edge. Have a look at the pictures. Circuit is provided below.
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| Front and Back of the DVM (Quiz: which is the Front and Back ?) |
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| DVM displaying Positive Voltage |
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| DVM displaying Negative Voltage |
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