Ohms Law Is The Same in All Industries!!!
Don Wilcher ŠNov. 8, 2005
I can remembered back in my Electrical Engineering DC Circuits 1 course the lecture on Ohms Law. The discussion focused on how Ohms Law is a basic tool that can be used to analyze & design simple and complex electrical dc networks. The three basic elements of the equation "I", "R", and "V" shows the functional relationship that is intrinsic to all electrical and electronic components and gadgets. Digital circuits can also be analyzed by breaking the basic logic gates down to their finite impedance elements. Digital data transmission and fan out/in circuit parameters are affected based on the basic intrinsic impedances within the logic device.
In designing subcircuits and subsystems, the interface requirements for interconnectivity all depend on the basic elemental relation of "I", "R", and "V" components. Working in the Auto Industry as an Hardware EE , specifications are written, circuits/subsystems are designed, and electronic components are selected. To expedite the design process, basic I/O circuit interfaces become standard book shelved building blocks that can be reuse in a multitude of vehicle applications. These basic I/O circuit interfaces consist of analog and digital functions that are adopted from component datasheets and design application notes. The core circuit from the datasheet is tweaked to meet the vehicle specifications mandated by the customer's requirements.
The Automotive electronic circuits used in the vehicle, again, are adopted from the component's datasheet. Consumer Electronic products can use Automotive electronic circuits by tweaking the function to meet the product's design specification. The electrical power switch interface circuit used on cell phones can easily use the ignition switch wiring design of an automobile. The reason is because of Ohms Law. The design/analysis feature of the Ohms Law equation for a cell phone is no different than the automotive switching application. The op-amp circuit used in hardwired signal comparison applications for medical instrumentation uses the same Ohms Law equation as in a consumer electronics product. Microcontrollers like the Freescale 68HC12 will work quite well in an industrial PLC (programmable logic controller) device for adding intelligence to a paint conveyor control panel. The temperature requirements of the target application is the critical element to take in consideration when selecting a subcircuit's component. In Automotive applications, the digital and microcontroller circuits require +5VDC supply source for proper and safe operation. To accomplish this design requirement is to use a voltage regulator chip like the 7805 device. The same automotive digital circuit application can be used in a cell phone by modifying the DC power supply requirements to a handle +3VDC voltage source. The key to this circuit modification is the use of the Ohms Law equation.
Therefore, to make a career change to one industry to another as an EE shouldn't require an extensive amount of training. Electrical-Electronic circuits are flexible and transportable elements and can be used in a multitude of industry application machines. The ability to take core circuit blocks and adapt them to a myriad of industry, consumer, medical, and automotive products is the innovation challenge for an Electrical Engineer. The underlining design/analysis tool that makes it possible is Ohms Law.
To illustrate this adaptability of design/analysis skill set philosophy I had a discussion with a Texas Instruments Engineering Manager wanting to use their newest ARM based microcontroller (MCU) product the TMS470R1x in an automotive application. The challenge is to take this ARM based MCU device used in computers and adapt it to an Automotive Integrated Power Module (IPM). The process used in making this product conversion change is a combination of Systems Engineering, circuit I/O mapping, and Ohms Law. Step 1 in this conversion process is to create a block diagram of a basic Body Control Module as shown in Figure 1.
With this basic block diagram available, the circuit I/O interfaces can then be mapped into the TMS470R1x ARM based MCU architecture. The next step is to create a Block Diagram of the IPM. This block diagram is generated using a service manual and knowing standard electronic circuit interfaces used in all consumer, medical, and industry products. Figure 2 shows the Block Diagram of the IPM.
With this architecture diagram available, the TMS470R1x ARM based MCU data sheet was obtained and reviewed. The critical area of the TMS470R1x device is the circuit blocks used to create its software and physical layer interface. This information will allow a 1 to 1 mapping of replacing the IPM's Freescale M68HC12B MCU with the TMS470R1x device. The Front Control Module (FCM) and the Power Distribution Center (PDC) sections are key to this 1 to 1 mapping design activity. Figure 3 shows how the TMS470R1x chip can replace the existing MCU component
Finally, Ohms Law will now play a role in the design of the circuit I/O interfaces by reviewing the signals the TMS470R1x will manage and process via the programmed embedded software. The voltage and impedance requirements of the interconnected circuit blocks will allow Ohms Law to finalize the circuit I/O interfaces for the application. After presenting the TMS470R1x Power Point design/analysis material, the TI Engineering Manager was quite impress with the technical information. To illustrate the career skill set transference process further, the robotics projects posted on this website and published in my two books use electronic circuit I/O interfaces originated from the Automotive Electronic Control Units I've developed for several OEM Car Manufacturers and Device Suppliers.
This Technical Essay illustrates a key area in EE Careers that is very important: mobility. Career mobility is critical in this age of overseas outsourcing, low wages, and work overload. The industrial experience obtained from real world projects can be transferred to a multitude of industries. As illustrated, a computer MCU can easily be used in an automotive application. Likewise, Automotive electronics can be used in another industrial areas and products for example, robotics. Doctors are able to migrate from one hospital to another because medicine doesn't change from location to location. If a Doctor knows how to check for a fever at one hospital, then the same basic medical practice can be applied at another health care facility. The same career mobility for EE's working in the Auto Industry can apply their knowledge of circuits and systems for the semiconductor sector. The reason for this seamless transference is Ohms Law Is The Same in All Industries. Thank you Georg Simon Ohm!!!!
Comments are welcome!