Comment by periblepsis on differential gain for mismatched \$g_m\$ in...
@Carl The context is for linear circuits (audio amplifiers, for example) and discrete designs. Also, just by the way, I bought a bevy of BJTs in TO-92 packages (about 22,000 of them) at 0.4 cents each....
View ArticleComment by periblepsis on Analyzing the following current mirror
@Isay R1 means you will need a product-log function (LambertW) to solve for Iout itself. Also, Q2 just eliminates the Early effect of Q3 while also providing a substantial part of the Iout current....
View ArticleComment by periblepsis on Having trouble understanding saturation mode in an...
Electric, Unless you really want a detailed understanding of more physical models than what diodes and current sources provide (if that's your goal then any book with "microelectronics" in its title...
View ArticleComment by periblepsis on Encountered a basic problem in BJT with absurd...
Funny that the writing says, "calculate the values of Icq, Vceq, ..." when the chart itself tells you the value of Icq being 30 mA and the value of Vceq being 3.4 V. Is that the way you also see it,...
View ArticleComment by periblepsis on Trying to replicate a full-wave rectifier circuit...
What exactly would you consider to be expected behavior? Where did you get this schematic? What's actually driving the BJT base?
View ArticleComment by periblepsis on How to find node voltage in this relatively simple...
Adam, I converted the 10 V source and the 40 Ohm resistor to its Norton. That gives a net 3.25 A source into Vx with a 40 Ohm resistor in parallel with the 6 Ohm resistor. So the equation to solve for...
View ArticleComment by periblepsis on What is the differential equation for this circuit?
Since there will be no current in the upper-right R resistor, all you have is two cases: (1) At near DC input, vout=vin; and, (2) at near daylight input, vout=vinRc/(R+Rc). So it must be that [1 +...
View ArticleComment by periblepsis on Protecting circuit from high voltage arc
@Hearth That might work, but for the extreme dynamic range of the leakage current measurement -- which spans 7 orders of magnitude.
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Answer by periblepsis for How to find the equivalent resistance in this...
Let's first set up the circuit into LTspice and get an answer:From the above, it's clear that \$R_{_\text{TH}}=\frac{200}{13}\:\Omega\approx 15.3846\:\Omega\$ (and that \$R_{_\text{TH}}\ne...
View ArticleComment by periblepsis on Darlington Pair Amplifer
@OfficialPyramid You only have one active drive quadrant, in concept. And I'm almost sure you have C2 bypassed with a wire that runs right through it. So the schematic may be badly composed. Get the...
View ArticleComment by periblepsis on LM741 for audio amplifier with 8ohm 10W speaker
Several things wrong. You aren't the designer and I'm not going to ask a bunch more questions, then design and explain something else. So I'm leaving this for others. Best wishes.
View ArticleComment by periblepsis on Inductor value effect on the performance of a buck...
Andromeda, One thing immediately comes to mind from a quick scan of the datasheet. With 4.7 uH, you likely need a capacitor to ground from Vc (in parallel to the added zero there.) Also, are you...
View ArticleComment by periblepsis on The role of the roll off factor in synchronization
Is that the book on SDR? If so, the author doesn't seem to be Harris. So is that quote coming from the book or from someone commenting about the book? Links and/or references, plus some more discussion...
View ArticleComment by periblepsis on Analysis of ramp generator with BJT PNP
Felipe, You can design a reasonable current source/sink that works over a temperature range and part variations that provides a current into a capacitor. This can be followed by a Schmitt trigger that...
View ArticleComment by periblepsis on Equivalent Resistance across terminals "in the...
@user486392 The main thing is to pick a ground (you can pick any one wire/node) and then just start removing any wires you can live without. In your new example case, set B to ground (or A) and erase...
View ArticleAnswer by periblepsis for Why does energy stored in a capacitor increase with...
The definition of capacitance is that the voltage difference between the plates is \$V_{_\text{C}}=\frac{q}{C}\$ or that \$C=\frac{q}{V_{_\text{C}}}\$ and \$q=C\cdot V_{_\text{C}}\$.The work done to...
View ArticleComment by periblepsis on In Q_point of NPN BJT, Should Vce or Vc be set to...
There's no bright line fixed rule. One significant factor is the allowed operating voltage difference. Another is temperature range and required gain stability over temp and part variation needed...
View ArticleComment by periblepsis on In Q_point of NPN BJT, Should Vce or Vc be set to...
One potential problem may show itself when allowing the collector voltage to get near the Vcc rail -- nearly zero collector current. Which means the dynamic range, the ratio of maximum (or quiescent)...
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Answer by periblepsis for Differences in Early Voltage \$V_A\$ in \$V_{CE}\$...
Most of the techniques for measuring \$V_{_\text{A}}\$ become relatively inaccurate as \$V_{_\text{A}}\to\infty\$. But this isn't a problem because the effect of basewidth modulation...
View ArticleComment by periblepsis on The 9V tongue test, but with a capacitor. How...
The battery would keep the tingle going longer.
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