Passive Component Manufacturers
Passive component manufacturers emerged from the last economic downturn with a renewed respect for building closer relationships with customers. This translates to an even higher emphasis on customer concerns during new product design and inventory management.
PCB footprints for passive components follow certain standards and can be time-consuming to create by hand. Use the right electronics search engine to save time and focus on your product design.
Resistors
Resistors limit the flow of current in circuits. They are important because they prevent too much current from reaching sensitive components like transistors, which can destroy them by overheating. They are available in a wide range of resistance values, from a few milliohms to about a gigaohm in IEC60063 ranges appropriate for their tolerance.
When designing a resistor circuit, the primary parameter is its resistance value. The accuracy of this value is indicated by its tolerance, which may be expressed as a percentage of the resistance value (for example +-5%). Other useful properties are long term stability and temperature coefficient.
Many resistors are manufactured in multiples of a single value for convenience. This can reduce assembly costs and facilitate a consistent assembly process. It can also help when multiple resistors of the same value are required, as in data bus pull up applications for example. This is often done by constructing them into multi-pole packages, such as the single inline (SIL) or dual inline (DIL) types.
All resistors dissipate energy as electric current passes through them, which is why they need to be rated for their power-dissipation rating, which indicates how much heat energy they can safely disperse without being damaged. The wattage rating can be quite different between resistor types; for example, a 2 watt carbon composition resistor will have a lower wattage rating than a wire-wound resistor of the same value.
Capacitors
Capacitors are a key element of Passive component manufacturers circuit boards. They pass alternating current and block direct current. They also store energy and release it when needed. This is similar to how a water tower stores water pressure for a town, but at a much smaller scale.
Basically, capacitors consist of two plates with a dielectric material between them. The size and surface area of these plates determine their capacitance value. The distance between the plates is also important. The closer they are, the greater the capacitance. The dielectric material’s permittivity is another factor that increases the capacitance.
The positive and negative charges on the two plates attract each other. However, they are prevented from joining forces by the insulating layer. In this way, the capacitor stores electric energy just like a battery stores chemical energy.
Besides acting as an electric energy storage device, capacitors can also be used to shunt DC current fluctuations in signal circuits or bypass AC voltages from the power supply. For instance, audio equipment uses multiple capacitors in parallel to shunt power line hum before it reaches the signal circuitry. This allows the signals to be transmitted without noise or distortion.
Inductors
Inductors store energy in the form of magnetic energy. They oppose sudden changes in current and are often called coils or chokes. The value of an inductor is measured by its inductance (H) in units called henries.
The ability of an inductor to store energy is related to its length and the frequency of the current that flows through it. It can also be affected by its material, such as copper or brass cores. The inductance of a coil can be increased by winding wire around a core made from ferromagnetic material.
As current flows through an inductor, it creates an induced voltage across its pins (or terminals). This induced voltage is proportional to the rate of change of current and the frequency of the changing current. This is why inductors are usually insulated from each other to prevent accidental contact which could result in a short circuit.
Inductors are used in a wide variety of applications including filtering, resonance and current limiting. They are also a critical component of transformers which increase or decrease voltages in power supplies and the large gray canisters you see on utility poles. Often combined with capacitors, inductors can create a noise filter which is useful in some audio & video circuits to dump DC current to ground and block AC ripple.
Switches
Switches are network devices that connect multiple local area network (LAN) segments by microprocessor and microcontroller filtering and forwarding data packets based on the destination MAC addresses. They operate at the data-link layer of the OSI model and support unicast, multicast, and broadcast communication. Switches also reduce unnecessary traffic broadcasts by recording the MAC address of each device that sends or receives a packet, then directing it to the appropriate port.
Unlike hubs, switches are capable of performing advanced functions like network cable consolidation, IP routing and quality of service settings. They offer more port capacity than hubs, ranging from 4 to 128 ports. They can support different types of network speeds, including Fast Ethernet (10/100 Mbps), Gigabit Ethernet (1Gbs), and 10 Gigabit Ethernet.
They can be unmanaged, managed or with a combination of features. Managed switches offer advanced capabilities such as port mirroring, which creates a mirrored image of network traffic and allows you to monitor the health of your networks. They can also offload some network diagnostic functions, such as intrusion detection and performance analytics, to save on hardware costs. Unmanaged switches have simple plug-and-play setup and use auto-negotiation between Ethernet devices to determine the best data rate for transmission. They are available in a variety of form factors, including desktop units for home or office environments; rack-mounted switches for deployment in wiring closets and data centers; and DIN rail mounted switches for industrial applications.