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Summary:
I was recently interviewed by EEWeb for the Featured Engineer edition. EEWeb, an electrical engineering publication, has many remarkable sections, including Analog Design, RF Design, tools, jobs, projects, and even a comic section. Of interest is the EEWeb forum, which is a growing discussion board organized in categories.
Measure a Bipolar Signal with an Arduino Board
Sunday, August 14th, 2011Summary:
Arduino is a popular family of open source microcontroller boards. Hobbyists, students and engineers all over the world use this platform to quickly design and prototype a microcontroller driven circuit. One of its interfaces with the analog world is the ADC. Since these boards are mostly designed around an ATMEL ATmega32 or ATmega168 microcontroller, the ADC has 8 inputs and 10-bit resolution, making it suitable for many applications.
Measure a Wheatstone Bridge Sensor Signal with an ADC
Saturday, July 23rd, 2011Summary:
I received a message from one of my readers asking me to help with a Wheatstone bridge circuit. Since my response to him bounced back, and this being an interesting subject, I decided to write this article. Here is what he writes:
Apply Thevenin’s Theorem to Solve a Negative Resistance Circuit, or Current Source
Monday, February 14th, 2011Summary:
The circuit in Figure 1 is a good example of applying Thevenin’s Theorem to solve a circuit with dependent supplies. It is a negative resistance circuit and it was posted in this forum with a call for solution verification for IL as a function of Vin. Since this fits very well with my plans to write more about Thevenin’s Theorem, I decided to post the solution here.
Build an Op Amp SPICE Model from Its Datasheet – Part 4
Monday, February 7th, 2011Summary:
Parts 1, 2, and 3 of this article show how to create a behavioral model of an operational amplifier based on the following parameters found in the datasheet: Input and output resistance, input capacitance, DC gain, offset voltage and gain bandwidth product. As an example I chose Analog Devices’ ADA4004 and built its behavioral model step by step. Figure 1 shows the model as we left off at the end of part 3.
Build an Op Amp SPICE Model from Its Datasheet – Part 3
Friday, December 31st, 2010Summary:
In Part 2, we left off at the open-loop bode plot. We saw that it resembles the datasheet. However, our op amp example, ADA4004 from Analog Devices, shows an extra pole after 1 MHz. Indeed, the phase starts dropping after 1 MHz and becomes 45 degrees at 17 MHz. Therefore, we need another pole in our model at 17 MHz.
Build an Op Amp SPICE Model from Its Datasheet – Part 2
Sunday, November 14th, 2010Summary:
Part 1 of this article shows how to create a behavioral model of an operational amplifier based on the following parameters found in the datasheet: Input and output resistance, input capacitance, DC gain, and offset voltage. As an example I chose Analog Devices’ ADA4004. Let’s continue building this model to simulate the Gain Bandwidth Product.
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