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Pease Porridge
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442 results found for Pease Porridge, displaying items 1 - 20
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June 25, 2009
Bob's Mailbox
HI BOB, I read your response to Arthur Williams in the April 23 column (“Bob’s Mailbox”). The answer as to whether or not to remove the ground plane underneath inductors is: it depends. If the inductors are cans or toroids, it does not matter as the fields are contained inside the inductor. If the inductors are air wound or chip inductors, it might be best to try...
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Bob Pease
June 11, 2009
What's All This Bridge Amplifier Stuff, Anyhow?
I was helping some engineers working on a strain-gauge preamp not too long ago. We had it functioning, but there seemed to be some bad linearity problems. We even set up a little calibrator and tried to get it linear, yet we kept getting odd errors, using the conventional amplifier setup per Figure 1. The guys said, “We don’t have to worry about precision or calibration because we’re calibrating it in ...
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Bob Pease
May 21, 2009
Bob's Mailbox
HI BOB, Regarding quad op amps (“Cdesign.com/ArtICles/ArtICleID/20895/20895.html">What’s All This ‘Free Amplifier’ Stuff, Anyhow?”), I thought I’d pass on this tidbit from my early days in the late 1970s. I was working at an industrial controls company on the east coast named Leeds & Northrup Co. (now defunct). (Yeah, I have collaborated...
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Bob Pease
May 7, 2009
What's All This Counting Stuff, Anyhow?
Once upon a time when I was about four years old, my father went up the road to buy a couple of piglets, and he took me along. We brought them home to our little farm in a burlap bag in the back of our pickup truck. I guess I must have thought this was quite exciting, because my mother thought I was overstimulated. She sent me in to the living room to take a nap, even though it was only 11 a.m. So, I lay quietly on the couch and tried to get to...
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Bob Pease
April 23, 2009
Bob's Mailbox
BOB, I’ve got 35 years as an electronics design engineer doing microprocessors, hardware, and quite a bit of analog. In the late 1970s, I was involved with two different slewrate- limited applications. One was control of the throttle and pitch of the props on patrol boats. The bridge could signal full ahead, and this condition would cause engine stalls. So, a slew-rate control was needed to bring the engine to full power and adjust the prop...
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Bob Pease
April 9, 2009
What's All This "Free Amplifier" Stuff, Anyhow?
One of my friends was working on a story. She observed correctly that an “ideal” op amp would have infinite gain and common-mode rejection ratio (CMRR)—and zero IB and VOS— and zero price. She conceded she would never get rich selling those op amps! But there is a zero-price op amp, and I have been using them for many years—over 40. Maybe you have too. Let’s assume I have used three-fourths of an LM324 for three tasks, and that is working...
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Bob Pease
March 26, 2009
Bob's Mailbox
DEAR MR. PEASE, The “Financial Floobydust” section of your latest piece is, I think, anything but floobydust (Jan. 15; ED Online 20410). I believe you have touched upon a fundamental weakness at the core of so much financial and macroeconomic modeling, black-box investing, and other quantitative aspects of high finance. As you...
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Bob Pease
March 12, 2009
What's All This Rock-Hopping Stuff, Anyhow?
Untitled Document I went on a hike last weekend. Some of the trail was uphill, some was downhill, and I hiked along fine (if slowly). That’s not a surprise. But when I had to hop across a tiny stream, ...
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Bob Pease
February 26, 2009
Bob's Mailbox
HI BOB, We know that the noise power generated in a resistor is proportional to temperature. If we have a resistor with a zero thermal coefficient so that the resistance is constant with the temperature, does the temperature of the resistor increase due to the thermal noise? (No, not even sub-infinitesimally! / rap) In other words, does the resistor noise create noise voltage or current in the resistor, which in turn heats the resistor to a ...
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Bob Pease
February 12, 2009
What's All This Time-Domain Stuff, Anyhow?
Last night, I was attacking a thorny problem and thought about the time domain. I think about circuits, as an engineer, in the time domain. When something happens, or changes, then something else can happen—or may start to happen. Is that something that I like? Or is it something I don’t like? I have used this analysis many times, as in “What’s All This Fuzzy-Logic Stuff, Anyhow? (Part 4)” (Nov. 6, 2000; ...
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Bob Pease
January 29, 2009
Bob's Mailbox
Hello to Mr. Bob Pease! In the datasheet for the LM135/LM235/ LM335, there is no mention of capacitive bypass (minimum acceptable, maximum acceptable). This publication also did not say anything: www.national.com/appinfo/tempsensors/files/temphb2.pdf. (I apologize for this omission. You are right. This info should have been...
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Bob Pease
January 15, 2009
What’s All This Raging Canal Stuff, Anyhow?
There’s an old folk song that goes, “Well, she’s gone, gone, gone, and she’s gone, gone, gone. I lost my true love on the Raging Canal.” Back in the 1840s, a bunch of local Connecticut businessmen decided, after seeing how well the 1825 Erie Canal was going, that a canal could enable commerce between Hartford and the upper Connecticut River. Steamboats could get around the rapids at Enfield, using this canal, which would also provide water for...
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Bob Pease
December 11, 2008
Bob's Mailbox
BOB, I read your article “What’s All This Analog Engineering Stuff, Anyhow?” (Oct. 2, p. 18, ED Online 19754) I totally agree that the need for trained analog engineers is not going away. (I am not so interested in training, but in education. /rap) I have been in analog...
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Bob Pease
December 3, 2008
Bob's Mailbox
Columnist Bob Pease takes on Alan Greenspan and ways to stay warm and save gas this winter in this bonus edition of Bob's Mailbox.
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Bob Pease
December 1, 2008
What's All This "Adjustable Slew Rate Stuff," Anyhow?
The other day, a guy wrote in requesting help. “How can I make an amplifier with adjustable positive and negative slew rates?” he asked. I instantly replied, “Easily,” and I drew this up. As soon as I got to work, I scanned and sent him the basic circuit (Fig. 1). You turn the P1 pot until the available current through R1 is adequate to give the desired maximum negative slew rate. Likewise, turn...
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Bob Pease
November 17, 2008
Bob's Mailbox
BOB, I’ve once again bumped into the limit of an op amp. A single op amp can provide gain or level shifting but not both at once. (I tend to disagree. A single op amp can do a lot of things. It can pat its tummy and rub its head and hop up and down on one foot and provide gain and offset. /rap) I’m feeling around for a way to do a circuit. Depending on what is happening at the time, one end or the other of the resistor may...
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Bob Pease
November 7, 2008
What's All This Floobydust Stuff, Anyhow? (Part 5B)
People keep asking me when they will get to see my latest Dead Car List, where I keep track of all the disabled and abandoned cars I see on the road. Alas, while I have a couple of grocery bags of raw data on dead cars, I have not been able to find time or priority to organize them into a list. I’ve been too busy for 15 years, writing columns and other technical stuff. Here’s the real problem. Cars now just about all look the same. It used to be that I could...
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Bob Pease
October 23, 2008
Bob's Mailbox
BOB, You said, “I don’t recall if I’ve ever seen this circuit in print” (“What’s All This PNP Stuff, Anyhow?” Sept. 11, 2008, p. 80; www.electronicdesign.com, ED Online 19605), regarding Figure 2. See: 1. P.J. Baxandall, E.W. Swallow, “Constant Current Source With Unusually High Internal Resistance And Good Temperature ...
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Bob Pease
October 9, 2008
What's All This Space Heater Stuff, Anyhow?
keep hearing people say that the cost of energy is forcing them to choose between paying for gas to get to work, or buying food, or heating the house, or paying the mortgage... So they scrimp as much as they can and then lose their house to foreclosure. That’s very unfortunate. I can’t tell you how to save money on groceries, but other people will tell you how to do that. I can’t tell you all the ways to burn less gas in your car, but it is possible...
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Bob Pease
October 2, 2008
What's All This Analog Engineering Stuff, Anyhow?
For many years, aficionados of digital circuits and computers have bragged that their rapid advances will leave all analog circuits lying in the dust. The analog business is shrinking, at least compared to the success of digital computers. Moore’s law has made sure of that for many years. The tiny transistors are smaller and faster than ever, even if they can’t stand off 5 V (Fig. 1). ...
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Bob Pease
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