Pressure sensor basics - solutions - Huaqiang Electronic Network

Probe domestic switch needle KG-300K, needle head diameter is 3.0mm, normally open switch needle

100V, 250mA, surface mount, high speed switching diode

TP-IP4220CZ6, 5V, 0.35PF breakdown voltage, 6V SOT

Shunuo varistor / ESD varistor / complete product range / Sunlord first-class agent

Sensitive components are elements that react to the variable being measured. For example, an elastic bellows can detect pressure and deform accordingly. The amount of deformation reflects how the sensitive element responds to the pressure level. This makes the elastic capsule a pressure-sensitive component. A sensor must not only be sensitive but also capable of transmitting its response effectively. In other words, it’s more than just a sensitive part—it needs to output a measurable physical quantity that can be easily transmitted over long distances. For instance, the deformation of an elastic bellows is a small geometric change, which isn't ideal for remote transmission. However, if this displacement is converted into a change in capacitor plate spacing, it becomes a pressure sensor with a capacitance output. Since electrical signals are the easiest to transmit, most sensors produce outputs such as voltage, current, resistance, inductance, capacitance, or frequency. Transmitters are developed from sensors. Any sensor that provides a standard signal is called a transmitter. Standard signals, like DC 4-20 mA, follow international standards and allow different devices to be integrated into a unified system. This ensures compatibility and ease of use across various applications. Sensors that don’t output standard signals need to be paired with specific instruments. To improve versatility, some sensors can be connected to a converter that transforms their output into a standard signal, making them compatible with meters or systems that require standard inputs. Converters can also transform one type of signal into another—for example, converting air pressure from 20 to 100 kPa into a 0-10 mA DC signal. Positional effect and continuous action: Positional effect, also known as switching action, refers to sensors that have only two output states across the entire input range—like "high" or "low." These are commonly used for alarms, interlocks, and sequence control. An example is our pressure switch. When continuous monitoring or adjustment is needed, a continuously acting sensor or transmitter should be used. The SS-evaporation type semiconductor strain gauge used in Nagano’s transmitters has several advantages: (1) It uses a new evaporation technology compared to traditional paste or diffusion methods. (2) It can measure pressures ranging from -0.1 to 0.3 MPa and up to 200 MPa. (3) It offers excellent durability and stability. Semiconductor strain gauges are manufactured using paste, evaporation, or diffusion techniques. Nagano’s transmitters, such as KM31 and KM10, combine a semiconductor strain gauge section, an inductive component (stainless steel diaphragm), and a pressure interface, all welded together for high reliability, shock resistance, and impact resistance. The manufacturing process for evaporated semiconductor strain gauges includes: (1) Depositing a layer of polysilicon on a SiO2 insulating film. (2) Using CVD plasma to deposit a SiO2 layer on a stainless steel separator. (3) Laser etching to shape the strain gauge from the polycrystalline silicon. (4) Evaporating electrode beams and attaching gold electrodes. (5) Depositing a protective SiNx layer via CVD plasma. Flameproof and intrinsically safe types are selected based on the flammable gas and the risk level at the installation site. (1) Flameproof type isolates the internal circuit from surrounding flammable gases, allowing it to be used in hazardous environments. (2) Intrinsically safe type ensures no explosion occurs under normal or fault conditions, such as short circuits or open circuits. It's suitable for highly explosive areas.