Sensors {if 0}- Education

We are in multi-sim and we're looking at the simulation of a simple AM detector circuit. This is in the circuits that came with your text. It is titled “Figure 09_26.MSM.” I encourage you to run this simulation. First of all let's see, we have an AM modulated signal here in the previous screen we had discussed how an AM transmitter and receiver, the basic blocks of how that works.

Just as devices have been made to measure certain physical quantities and repeat that information in the form of DC electrical signals (thermocouples, strain gauges, pH probes, etc.), special devices have been made that do the same with AC. It is often necessary to be able to detect and transmit the physical position of mechanical parts via electrical signals. This is especially true in the fields of automated machine tool

If a strip of conductive metal is stretched, it will become skinnier and longer, both changes resulting in an increase of electrical resistance end-to-end. Conversely, if a strip of conductive metal is placed under compressive force (without buckling), it will broaden and shorten. If these stresses are kept within the elastic limit of the metal strip (so that the strip does not permanently deform), the strip can be used as

An interesting phenomenon applied in the field of instrumentation is the Seebeck effect, which is the production of a small voltage across the length of a wire due to a difference in temperature along that wire. This effect is most easily observed and applied with a junction of two dissimilar metals in contact, each metal producing a different Seebeck voltage along its length, which translates to a voltage between the

PARTS AND MATERIALS Two 6-volt batteries Two NPN transistors—models 2N2222 or 2N3403 recommended (Radio Shack catalog # 276-1617 is a package of fifteen NPN transistors ideal for this and other experiments) Two 10 kΩ potentiometers, single-turn, linear taper (Radio Shack catalog # 271-1715) Two 22 kΩ resistors Two 10 kΩ resistors One 100 kΩ resistor One 1.5 kΩ resistor Resistor values are not especially critical in this experiment, but have been chosen to provide high voltage

We're concluding Section 11.1. We start out with a discussion of common-mode versus differential-mode gain. Differential-load voltage gain is the gain given to a voltage that appears between the two input terminals. It represents two different voltages on the inputs. Recall that a differential amplifier amplifies the difference and with an operational amp, the input stage is a differential amp so it will amplify the difference between the two voltages on

PARTS AND MATERIALS 6 volt battery Potentiometer, single turn, 5 kΩ, linear taper (Radio Shack catalog # 271-1714) Small “hobby” motor, permanent-magnet type (Radio Shack catalog # 273-223 or equivalent) For this experiment, you will need a relatively low-value potentiometer, certainly not more than 5 kΩ. CROSS-REFERENCES Lessons In Electric Circuits, Volume 1, chapter 2: “Ohm’s Law” LEARNING OBJECTIVES Rheostat use Wiring a potentiometer as a rheostat Simple motor speed control Use of voltmeter over ammeter

Every meter impacts the circuit it is measuring to some extent, just as any tire-pressure gauge changes the measured tire pressure slightly as some air is let out to operate the gauge. While some impact is inevitable, it can be minimized through good meter design. Since voltmeters are always connected in parallel with the component or components under test, any current through the voltmeter will contribute to the overall current

A very important measurement in many liquid chemical processes (industrial, pharmaceutical, manufacturing, food production, etc.) is that of pH: the measurement of hydrogen ion concentration in a liquid solution. A solution with a low pH value is called an “acid,” while one with a high pH is called a “caustic.” The common pH scale extends from 0 (strong acid) to 14 (strong caustic), with 7 in the middle representing pure water (neutral): pH

PARTS AND MATERIALS 6-volt battery Electromagnet made from experiment in previous chapter, or a large spool of wire It would be ideal in this experiment to have two meters: one voltmeter and one ammeter. For experimenters on a budget, this may not be possible. Whatever ammeter is used should be capable measuring at least a few amps of current. A 6-volt “lantern” battery essentially short-circuited by a long piece of

PARTS AND MATERIALS One N-channel junction field-effect transistor, models 2N3819 or J309 recommended (Radio Shack catalog # 276-2035 is the model 2N3819) One 6 volt battery One 100 kΩ resistor One light-emitting diode (Radio Shack catalog # 276-026 or equivalent) Plastic comb The particular junction field-effect transistor, or JFET, model used in this experiment is not critical. P-channel JFETs are also okay to use, but are not as popular as N-channel transistors. Beware that

Most of us have experienced some form of electric “shock,” where electricity causes our body to experience pain or trauma. If we are fortunate, the extent of that experience is limited to tingles or jolts of pain from static electricity buildup discharging through our bodies. When we are working around electric circuits capable of delivering high power to loads, electric shock becomes a much more serious issue, and pain is

The bipolar junction transistor (BJT) was named because its operation involves conduction by two carriers: electrons and holes in the same crystal. The first bipolar transistor was invented at Bell Labs by William Shockley, Walter Brattain, and John Bardeen so late in 1947 that it was not published until 1948. Thus, many texts differ as to the date of invention. Brattain fabricated a germanium point contact transistor, bearing some resemblance to a

An op-amp with no feedback is already a differential amplifier, amplifying the voltage difference between the two inputs. However, its gain cannot be controlled, and it is generally too high to be of any practical use. So far, our application of negative feedback to op-amps has resulting in the practical loss of one of the inputs, the resulting amplifier only good for amplifying a single voltage signal input. With a

Centuries ago, it was discovered that certain types of mineral rock possessed unusual properties of attraction to the metal iron. One particular mineral, called lodestone, or magnetite, is found mentioned in very old historical records (about 2500 years ago in Europe, and much earlier in the Far East) as a subject of curiosity. Later, it was employed in the aid of navigation, as it was found that a piece of this

By introducing electrical reactance into the feedback loops of op-amp amplifier circuits, we can cause the output to respond to changes in the input voltage over time. Drawing their names from their respective calculus functions, the integrator produces a voltage output proportional to the product (multiplication) of the input voltage and time; and the differentiator (not to be confused with differential) produces a voltage output proportional to the input voltage�

PARTS AND MATERIALS High-quality “closed-cup” audio headphones Headphone jack: female receptacle for headphone plug (Radio Shack catalog # 274-312) Small step-down power transformer (Radio Shack catalog # 273-1365 or equivalent, using the 6-volt secondary winding tap) Two 1N4001 rectifying diodes (Radio Shack catalog # 276-1101) 1 kΩ resistor 100 kΩ potentiometer (Radio Shack catalog # 271-092) Two “banana” jack style binding posts, or other terminal hardware, for connection to potentiometer circuit (Radio Shack catalog # 274-662 or

For ease of drawing complex circuit diagrams, electronic amplifiers are often symbolized by a simple triangle shape, where the internal components are not individually represented. This symbology is very handy for cases where an amplifier’s construction is irrelevant to the greater function of the overall circuit, and it is worthy of familiarization: The +V and -V connections denote the positive and negative sides of the DC power supply, respectively.

It is very important to keep in mind that the “normal” contact status of a process-actuated switch refers to its status when the process is absent and/or inactive, not “normal” in the sense of process conditions as expected during routine operation. For instance, a normally-closed low-flow detection switch installed on a coolant pipe will be maintained in the actuated state (open) when there is regular coolant flow through the