1/ Capacitors and resistors have parasitic inductance, about 0.4nH for surface mount and 4nH for a leaded component.
对于表贴阻容元件有0.4nH的寄生电感，而直插阻容元件有4nH的寄生电感。
2/ If you don"t want a high bandwidth transistor to oscillate place lossy components in at least 2 of the 3 leads. Ferrite beads work well.
为避免高频晶体管震荡，放置几个损耗元件，例如磁珠。
3/ When taking DC measurements in a circuit and they don"t make sense, suspect that something is oscillating.
测不出电路中的直流量，可能某个元件引起了震荡。
4/ Opamps will often oscillate when driving capacitive loads.
驱动容性负载时运放容易震荡。
5/ The base-emitter voltage Vbe of a small signal transistor is about 0.65v and drops about 2mV/deg C. Vbe goes down with increasing temp.
小信号晶体管的基射极压降Vbe约为0.65v，随温度每升高1摄氏度Vbe下降2mV（负温度系数）。
6/ Multiply 0.13nV by the square root of the ohmic value of a resistor to find the noise in a 1Hz bandwidth. Then multiply by the square root of the BW in Hz gives the total noise voltage.bootstrapped
噪声电压/频率=0.13nV *√ohm * √Hz
n：信号带宽单位Hz
R：电路阻抗单位ohm
7/ Johnson noise current goes down with a increase in resistance.
约翰逊噪声（热噪声）电流随电阻的增加而减小。
8/ The impedance looking into the emitter of a transistor at room temp is 26Ohm/Ie in mA
室温下晶体管发射极阻抗与射极电流的关系为26ohm/mA 。
9/ All amplifiers are differential in that they are referenced to ground somewhere.
所有放大器的特性参数因其参考地的不同而不同。
10/ Typical metal film resistor has a temp coef of about 100 ppm/deg C
典型金属膜电阻的温度系数是100 ppm/℃。
11/ The input noise voltage of a quiet op amp is 1nv/sqrt(Hz) but there are plenty available with 20nV/sqrt(Hz). Op amps with bipolar front-ends have lower voltage noise and higher current noise than those with FET front-ends
虽然低噪运放的输入噪声电压是1 nV / √Hz但是很多应用是在20nV/ √Hz 。相比于场效应管型前端放大电路，具有双极型前端放大电路的运放具有低电压噪声和高电流噪声的特性。
(以上由地瓜patch/范尼斯特鲁伊于2010-1-11日翻译完成)
12/ Using an LC circuit as a power supply filter can actually multiply the power supply noise at the filter"s resonant frequency. Use inductor with low Q to overcome this.
将LC电路用作电源滤波器时，若LC滤波器工作在共振频率下将成倍增加电源噪声。用低Q值电感作为电源滤波器将会取得更好效果。
13/ Use comparators for comparing and op amps for amplifying and don"t even think of mixing the two.
比较器用作比较，运放用作放大。不要将两者混淆。
14/ Ceramic caps with any other dielectric other than NPO should only be used for bypass applications.
除NPO类电介质外的其他陶瓷电容只能用作旁路电容。（NPO电容器是电容量和介质损耗最稳定的电容器之一）。
15/ An N-channel enhancement-mode FET needs +ve voltage on the gate-source to conduct form drain-source.
N沟道增强型场效应管需在栅—源端接入正向电压，来控制漏—源端的导通。
16/ Small signal JFETS work very well as low-leakage diodes by connecting drain & source together in log current-to-voltage converters and low leakage input protection. Small signal bipolars with b-c tied together will also make nice low-leakage diodes.
在电流到电压的转换以及低漏电流输入保护的应用中，将小信号结型场效应管的漏端和源端短接用作低漏电流二极管，表现得很好。将小信号双极性晶体管的基极和集电极短接也是极好的低漏电流二极管。
17/ With low pass filter use Bessel for least amount of overshoot in the time domain, and Cauer (or elliptic) for fastest rolloff in the freq domain.
贝塞尔型低通滤波器在时域上有最少的过冲量，而切比雪夫型在频域上有最快的衰减速度。
18/ dB is always 10 times the log of the ratio of 2 powers.
dB = 2*10*lg(A/B)。（这个2是A/B的乘方，放到式子前边）。
19/ At low frequencies, the current in the collector of a transistor is in phase with the applied current at the base. At high frequencies the current at the collector lags by 90deg. You must appreciate this simple fact to understand high frequency oscillators.
低频应用中，晶体管集电极与基极电流的相位相同；在高频，集电极电流相位落后基极90度。在应用高频振荡器时要重视这个因素。
20/ The most common glass-epoxy PCB material (FR4) has a dielectric constant of about 4.3 To make a trace with a characteristic impedance of 100 Ohm, use a trace thickness of about 0.4 times the thickness of the board with a ground plane on the opposite side. For a 50Ohm trace make it 2 times the thickness.
PCB电路板所最常用的玻璃纤维/环氧树脂（FR4）的介电常数约为4.3。想要做一条阻抗为100ohm的导线，则导线厚度为电路板厚度加上板背面铺地铜箔的厚度的0.4倍。50ohm的导线就是100ohm导线厚度加倍。
21/ If you need a programmable dynamic current source, find out about operational transconductance amps. Most of the problem is figuring out when you need a programmable dynamic current source.
运算跨导放大器能够用作可编程动态电流源，最主要的是搞清楚什么情况下需要这个电流源。
22/ A CMOS output with an emitter follower can drive a 5V relay nicely as the relays normally have a must-make spec of 3.5V. This saves power and require no flyback components.
CMOS输出电路配一个射极跟随器可以很好地驱动5v继电器，对驱动电压标称3.5V的继电器表现同样良好，这样即节省了功率又无需反激式元件。
23/ Typical thermocouple potential is 30uV/degC. Route signals differentially, along the same path, avoid temp gradients. DPDT latching relays won"t heat up when multiplexing these signals.
标准热电偶电势为30uV/degC。沿着同一线路差分布线避免因温度梯度的影响。复用这些信号线时使
用双刀双掷所存继电器，不会加热信号线。
24/ You should be bothered by a design that looks messy, cluttered or indirect. This uncomfortable feeling is one of the few indications that there"s a better way.
看起来曲折杂乱的设计会使人烦躁，这种不舒服的感觉表明还有更好的设计方式
25/ Avoid drawing any current from the wiper of a potentiometer. The resistance of the wiper contact will cause problems (local heating, noise offsets etc.)
调节电位器时，要避免电位器的动触点拉带出任何电流，动触点接触点电阻会引起很多问题，如局部加热，噪声偏移等
26/ Most digital phase detectors have a deadband where the analog output does not change over the small range where the 2 inputs are coincident. This often-ignored fact has helped to create some very noisy PLL"s (Use a high val bleeding resistor to always ensure current flow in the deadband)
大多数数字鉴相器都有一个死区，在死区模拟输出在很小的范围上不能调节，2路输入会交叉干扰。这个经常被忽视的因素会引起很大的锁相环噪声。用一个大泄流电阻确保死区的注入电流可解决这个问题
(以上由地瓜patch/范尼斯特鲁伊于2010-1-24日翻译完成)
27/ The phase noise of a phase-locked VCO will be at least 6dB worse than the phase noise of the divided reference for each octave between the comparison frequency and the VCO output frequency. Avoid low-comparison frequencies.
28/ You can almost always determine the leads of a bipolar transistor with an ohm meter. b-e and b-c junctions will measure like a diode with the b-c junction reading slightly lower than the b-e junction when forward biased.
29/ For low distortion, the drains (or collectors) of a differential amp"s front-end should be bootstrapped to the source (or emitter) so that the voltages on the part are not modulated by the input signal.
30/ If your design uses a $3 op amp, and you will be making a thousand of them, you have just spend $3000. Are you smart enough to figure out how to use a $.30 op amp instead?
31/ The Q of an LC tank circuit is dominated by the losses in the inductor in terms of series R. Q=omega.L/R
32/ Leakage current doubles for every 10degC increase in temp.
33/ When inputs to most JFET op amps exceed the common-mode range for the part, the output may reverse polarity. This artifact will haunt the designers of these parts for the rest of their lives, as it should!
34/ Understand the difference between "make-before-break" and "break-before-make" when you specify switches. 35/ 3 Terminal voltage regulators in the TO-220 packages are wonderful parts. They are cheap, rugged, thermally
protected and very versatile. Use them virtually any place where you need a protected power transistor. They also make nice AM power-modulators.
36/ Use step recovery diode where you need fast edges under 100pS (hot-carrier is even faster)
37/ The old 723 regulator is still one of the lowest noise regulators around! (2.5uVrms 100Hz-10k)
38/ You can make a very simple oscillator with one diac, cap and a resistor.
39/ NPN transistors are normally superior to their PNP counterpart in performance.
40/ Typical spec in some databooks should read "Seen it once". Always work with the worst spec of the part when doing a design.
41/ Don"t just copy circuits from application notes without understanding completely how it operates, and the reason for the choice of values.
42/ Dealing with crystals, make sure you understand the difference between series and parallel resonant. In a circuit, crystal frequency can generally be slightly lowered by placing a inductor in series and increased by a capacitor in series.
43/ Power MOSFETS on-resistance will have a -ve temp coef and not +ve at low current levels. This is important to remember when paralleling devices.
44/ Lowest noise figure of a RF transistor is not normally where the input is perfectly matched.
45/ Many un-stable RF devices can be made stable by loading the input or the output by a simple resistor, either in series or parallel.
46/ You trade gain for bandwidth.
47/ Push-pull power invertors using bipolars are risky and can saturate the core because of hysteresis stepping (use power fets)
48/ The Al value of a core will increase up to 50% or more under current transients.
49/ Be aware of leakage inductance when switching. V=L(dI/dt)
50/ The harder you turn-on a power transistor, the longer it will take to turn off.( the part where you burn the joules in the device)
51/ Always remember the Miller guy.
52/ In fault-finding a circuit, don"t overlook the obvious. (is there power?)
53/ What is a ground loop, and how to avoid it.
54/ 120 is a better number than 240 when using LM3XX type adjustable regulators.
55/ The lower comparator in the old 555 may have quite a long storage time.
56/ ZERO-ESR caps may do more harm than good.
57/ A correctly configured audio power amplifier will give more distortion in Class-AB, not less, because of the abrupt gain changes inherent in switching from A to B every cycle.
58/ Be a STAR when it comes to ground matters.
59/ Know when you need to use a Zobel network.
60/ Use current mirrors and mirror your current.
61/ Heatsink eff decreases with height above sealevel.
62/ A matt-black heatsink is much better than a shiny one.
63/ Ignoring secondary breakdown can be costly.
64/ Understand fuses and fuse ratings, fast and slow. Do you know when to use a semiconductor-fuse?
65/ Charge balancing resistors are a must when stacking serie-parallel high voltage capacitor banks.
66/ You must understand DC-restoration otherwise you will have a hard time designing Z-modulation
in CRT circuits.
67/ Display 6 vert div low freq on a scope, increase the freq (make sure the source is constant amplitude) until display drops to 4.2 div. That is the true 3dB BW of the scope. (scope-source impedance should be matched)
68/ Doing a measurement with your DMM in the ACV position on your DC circuit will give a quick indication of any excess ripple on the supply when you don"t have a scope at hand.
69/ Dly timebase on a scope is very useful once you figured out when, why and how to use it.
70/ Know what to expect before you measure, otherwise any measurement is meaningless.
71/ Op amps. Output will swing in the direction that will force the inv-input level to try come closer to the non-inv input level.
72/ Understand virtual ground, slew-rate, CMRR and PSRR. (CMRR decrease with increase in freq)
73/ Making measurements near a spec-analalyzer"s noise floor will give 3dB errors.
74/ Understand the phase-noise limitations of the analyzer when making such measurements on oscillators.
75/ In a LC oscillator add some C with -ve temp coef to cancel the +ve temp coef of the L for min drift with temp. 76/ Less drift will result from making C with a few parallel caps, to reduce the heating effect of the oscillating current when spread out over a larger plate area.
77/ You will get more tuning range with the same LC combination in a Clapp than in a Colpitts circuit.
78/ High-Q tuned LC filters will have more insertion loss.
79/ Williams"s Rule (Guru at Linear Tech) for precision op amp circuits: " Always invert (except when you can"t)"
80/ Cuk is not a kind of locomotive.
81/ If you don"t know how to make a design better, find out what makes it worse.
82/ Sometimes you know just enough to be dangerous.
83/ Impedance will reflect back as the square of the turns ratio.
84/ If you could design a component with the characteristics of a finger it could cure many design problems and you will be rich.
85/ Get nervous when the customer you are trying to help doesn"t even have a scope.
86/ Specs quoted by reps always exceed those by Engineering.
87/ A bad (Engineer) workman always blames his tools.
88/ Don"t believe everything that a SPICE program spits out.
89/ It is easy to get the color code of a 1kOhm and 12Ohm resistor mixed up when you are in a hurry.
90/ I bet one could write a thesis about the ability of probes to get tangled-up on a bench.
91/ DMM can upset sensitive circuits from noise generated inside it.
92/ When probing directly on a crystal of a uP, use 10kOhm or so resistor in series with the probe tip to prevent loading from stopping the osc.
93/ It is easier to see what is happening on the ports using a scope when you trigger one chan against the cpu clock.
94/ National once made a bad op amp many years ago that some Engineers referred to it as "Jelly Beans"
95/ The moment you can start to notice distortion on an oscilloscope it is already way past being acceptable.
96/ Be big enough to say "I don"t know", people will respect you more.
97/ The best designer is often working in the marketing department.
98/ Some remarkable discoveries/inventions were made by people that knew very little about the subject. Don"t fall into a groove in you thinking process.
99/ The Peter-Principle : Everybody will be promoted up to his own level of incompetence.