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Answer by periblepsis for Counting relay circuit
At the moment im using a Jaycar KA1732 kit but its not quite what Ineed: settable counts between 1-500 and settable wait times between each relay activation of 1-60 seconds.That device has the...
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Answer by periblepsis for Op-amp question: Is this circuit possible?
Start by examining each half in isolation, as voltage dividers:$$\begin{align*}v_-&=\frac{v_n\,\cdot\, Z_{rn}\,+\,v_s\,\cdot\,Z_n}{Z_n\,+\,Z_{rn}}\\\\v_+&=\frac{v_p\,\cdot\,...
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Answer by periblepsis for Substitute 2N3055 with 2SC5200 in the John Linsley...
That design from Hood looks a little off, to me. Partly because I think the 2N3906 may run out of gas given certain drive cases. It also seems to be running very hot (a bit high on the quiescent...
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Answer by periblepsis for Thévenin: Weird instructions
quick high-level overviewRaquel, One of the problems we each face at some point when first learning about parts of the world we can't directly touch and feel with our own senses is about "breaking"...
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Answer by periblepsis for Uncertainty of transistor hfe/beta values
I just pulled (11) PNP 2N4403 (any small signal BJT that isn't in a TO-39/TO-205AD package, or better, is beneath my notice) from one 1000-bag laying about. Using a base current set to...
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Answer by periblepsis for LED driving circuit, related to MOSFET V(gs)
You can see from this:That if the drain and gate are tied together and the drain current is modest, then at most you need \$V_{_\text{GS}}\le 4\:\text{V}\$. There's also a transfer curve, later:That...
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Answer by periblepsis for Parallel circuit calculations
I'm going to make a huge guessing leap about this lab work and imagine that you are dealing with a tungsten lamp and that your lab trainer made a resistance measurement of the lamp, when cold; but you...
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Answer by periblepsis for Rigid 4x4 keypad decoder - voltage drop
I thought I'd just suggest something for you to consider in the future. It has just enough features to be generally useful.keypad and scan driverHere's what I'd start with, with respect to the input...
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Answer by periblepsis for How can I make a current source with no transistors...
in generalAs others have pointed out, a voltage source and a resistor can be used. But... with the following rule:Start with a lot of voltage and throw almost all of it away!If you know the voltage...
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Answer by periblepsis for Is it possible to do water detection with a single...
research, research, researchThere are articles on the topic of charge storage in water in the research literature. I'm not going to list any of them here because I'd have to first review them for...
View ArticleAnswer by periblepsis for Getting temperature dependence for a beta...
I'm going to ignore the \$V_{_\text{THN}}\$ term and focus on the remaining term, which is a product of two functions.If you have the product of two functions, call them \$P\$ and \$Q\$, so that...
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Answer by periblepsis for Difference between MC1496 / LM1496 balanced modulator
The LM1496 from National Semi (I think it was available at least by 1976, possibly earlier) was listed in the National databooks as a direct replacement for the MC1496 (which came out in 1972, I...
View ArticleAnswer by periblepsis for How to determine in a nonlinear circuit with...
In 4.3(a) start by asking if the \$-3\:\text{V}\$ is more negative than either or both of the sources at the diode anodes. The answer is yes in this case. So you know that at least one of the two...
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Answer by periblepsis for Effect of Vbe on Ic for a BJT
@periblepsis yes I would be grateful if you could elaborate on your point of view –Xavier@periblepsis I'm still interested in your point of view. –internetI'll try to get straight to the point. I can...
View ArticleAnswer by periblepsis for Why does saving addresses on a stack give us the...
This one is easy. It says "(b) In a memory location associated with the call, so that a different location is used when the subroutine is called from different places".In the case of recursion,...
View ArticleAnswer by periblepsis for Initial condition across capacitor - RLC
In the very long time between \$t=-\infty\$ and \$t=0^-\$, the current in the inductor \$L\$ will stop changing. Because of \$V_L=L\cdot \frac{\text{d}}{\text{d}t}I_L\$, this means \$V_L=0\:\text{V}\$...
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Answer by periblepsis for Two-terminal current source review
There's a couple of old school (you should readily find them on the web -- Supertex for sure has appnotes on this -- now on Microchip's site) methods that provide limited current while also working...
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Answer by periblepsis for Theoretically, if we send a square wave, of...
Wrong: "with harmonics at integer multiples". The square wave is every odd integer multiple, starting at 1. Not at all integer multiples.Right: "main component would be phase shifted by -45 degrees"....
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Answer by periblepsis for DC circuit and capacitor
Since there are resistor values given, but no capacitor values provided, I can surmise that the problem is about the values on the capacitors after a very long time.The schematic is also missing a...
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Answer by periblepsis for TAOE3, Exercise 2.13 -> Verify that a 8°C rise will...
Straight from Ebers-Moll:$$ \frac{I_{C_2}}{I_{C_1}}=\exp\left(\frac{\Delta V_{_\text{BE}}}{V_T}\right)$$(You should be able to derive this.)So, assuming about \$-2.1\:\text{mV}\$ change in...
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