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Hendon Semiconductors – Microelectronics Design

Products include integrated circuits (silicon chips) in Bipolar, Bi-CMOS and CMOS technologies, thick film hybrids (ceramic substrate) and surface mounted printed circuit board assemblies and modules.

Hendon Semiconductors – Microelectronics Design

History -“The Hendon business site in Adelaide, South Australia has been a long established integrated circuit design and wafer fabrication facility in Australia, from its Philips semiconductor background up to 1997…”

Hendon Semiconductors

Thick Film Hybrid Technology

The advantage of ceramic hybrids over fiberglass printed circuit is their high reliability due to their inherent rugged construction with the following advantages:

Hendon Semiconductors Pty. Ltd
ABN: 17 080 879 616, 1 Butler Drive, Hendon, South Australia 5014, Australia.

3-1/2 Digit ICL7107 DPM Digital Panel Meter

This is a Digital Panel Meter based on ICL7107. This was the workhorse Digital Readout chip before Low power uC designs were developed. Even now it is the easiest way an analog parameter can be displayed in an instrument.

Instrumentation and Measurement Circuits

3-1/2 Display is just enough resolution for recording process data or troubleshooting equipment. With 4-1/2 you notice the problems of thermoelectric EMF of probes and connectors. That is one reason gold plating is used another being low contact resistance. In 4 1/2 the reading can change due to contact resistance too, if the input impedance of the analog signal conditioning is low or the protection diodes, RC filter caps are leaky.

ICL7107 DPM Digital Panel Meter

When you measure an analog parameter from a sensor; you attenuate or amplify it, to scale to the A/D converter range. You also need to protect or isolate the analog front end from high energy mis-connections, which will happen during field use. The operator should not get injured from any high energy leakage while measuring.

Resolution is the finest detail you can enumerate in a parameter or object. You can say the crowd was 3000 or 4000 people. Here 1000 is the resolution, finer data does not matter here. You would also hear things like, there were 80 to 90 boys in that classroom. 10 is the resolution there.

Accuracy is how precise a statement or number is. If there was 85 boys in that class, the above statement is accurate. If there was 65 boys, the measuring method or process needs calibration or examination.

In this circuit, the plastic caps should be of very low leakage. Multilayer plastic caps are good for instrumentation.