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Hi. Please e-mail me at ambertec@ieee.org so I can reply to you with some crystal test configurations I've used. One thing you might be able to get to directly is "Check Crystal Impedance" in Electronic Design, November 9, 1992, page 61. John Dunn ambertec@ieee.org

At RF and microwave frequencies, PIN diodes are used as variable resistances for gain control.

If you really want to see if an interview candidate really has "what it takes", ask for a description and explanation of what is listed in the candidate's resume. Ask that person to tell you exactly what he/she did and what were the reasons for that. It really is a very revealing...

Hello, Kiev. It would be interesting to know the pF to fruit ratio involved! One problem of measuring a small capacitance is doing so in the presence of the capacitance of the cable that feeds your parallel plates. Please see if you can find a copy of Electronic Design for December 5, 1991...

The structure you describe sounds like it can be taken as a capacitor whose voltage withstanding properties are in question. Please send me an e-mail. Then I can send you a copy of an item I published some years ago on testing capacitors for voltage withstanding properties. It may have bearing...

Please take a look at: http://www.drzyzgula.org/bob/text/fr.tom/awg.txt There is a really very nice wire table there with much of the information you need. Good luck. John Dunn ambertec@ieee.org

Capacitors and inductors both are used to store energy in their respecitve ways so that all of that stored energy can be retrieved. To simplfy (I hope): Capacitors store energy by acquiring a charge called Q for which a capacitance C will yield a voltage V. The relationship between them is Q =...

Does anyone know of a transient absorbing diode tailored, as it were, to MIL-STD-704A service a'la the 1N5555, but with a higher power capability than the 1N5555? (A lot!! more power capability actually.) Thank you. John Dunn - President Ambertec, Inc. ambertec@iee.org

One caution about the TIP series. It was originated by Texas Instruments and then later copied by Motorola, now ON Semiconductor. Although the data sheets were essentially the same, two samples of the TIP29C from these two companies parametrically (Icbo, Vceo and beta) met all of their minimum /...

Please try to find a copy of Electronic Design, December 5, 1991 where on page 113 is an Idea For Design entitled "Vary Capacitance To Positive Or Negative". I submitted that item. It describes making variable capacitances of values to as many µF as you'd like, including negative...

Hi, Curt. Even if someone claims to have done this successfully, your sense of caution is well placed. There is a finite possibility of the output of one amplifier damaging the other and who'd want to risk that? Also, damage possibilities aside, each amplifier was surely designed on the...

Another requirement for patentability is that the invention should not be "obvious" to someone "skilled" in the art. If your item is electronic/optoelectronic in nature and yet you yourself are not knowledgable in those fields, you should have someone whom you can trust...

I am very happy to report that the building wiring in my son's dormitory has been re-done and brought up to modern code. "Grandfathering" may have its place, but that old wiring dated from the 1920s when the building was first electrified and it was NOT safe! I made many...

My son just entered his freshman year in college in Boston and moved into a nearby dormitory where I discovered that none of the wall outlets in his room have any ground connection at the wall plates, a situation which is both dangerous and, I suspect, illegal. I have been given to understand...

Another aspect of short circuits is that they are not really zero ohms because the involved metals are not superconductors. That can be useful when troubleshooting circuit boards where copper foil runs can be very long, even running to the full physical span of the board.<br><br>Once you've...

There is a special case of RMS determination which might be worth mentioning.<br><br>If we have a square wave of zero volts to a unipolar peak of &quot;E&quot; volts (typical of much logic circuitry with zero and +5 volts) and some particular duty cycle, the average value of that waveform is E...

Hello, Kunalw.<br><br>May I suggest looking at it this way. An operational amplifier (op-amp) has two inputs which we call the inverting input and the non-inverting input. With an idealized op-amp, which means one having infinite gain and infinite bandwith, in the response of whatever circuit...

Azmi is essentially correct. However, there are so-called &quot;non-inductive&quot; wirewound resistors in which the resistive wire element is given a bifilar construction. That tends to reduce the inductance the resistor would otherwise have, although not eliminate it altogether.<br><br>John...

There is a facet of power factorcorrection which should be mentioned. Assuming a sinusoidal input voltage, the wattage consumed by some load is the product of the that sinusoidal voltage times that part of the current waveform which comprises a sinusoidal current in phase with that input...

Phase sensing relays are offered by some relay manufacturers. If the three-phase phasing is &quot;wrong&quot;, actuation of three phase loads, such as some motors used in particularly critical applications, can be inhibited. It may be worse to have a motor run in the wrong direction than to have...