Leads are two small wires extending from the poles of an electrical component (such as a resistor, capacitor, or semiconductor device) and used to connect the component to a circuit or other components. They may also be called hookup wires, appliance wires, or simply leads.
Wire predates the use of connectors and can be traced back to the early days of electricity. As electronics technology developed, the need for reliable connections between electronic components became increasingly apparent. The development of various insulating materials such as rubber and later synthetic polymers further facilitated the use of wire in connecting electronic components. As electronics expanded into industries such as telecommunications, medical devices, control panels, military equipment, and consumer electronics, the need for specialized wire with specific properties grew.
Connector lead considerations
Wires can be attached to connectors using a variety of techniques and methods to ensure a reliable, secure connection.
1.Soldering is a widely used method of connecting wires to connectors. In this process, the exposed conductor of the wire is tinned with solder and the corresponding terminal or pin on the connector is also tinned. The tinned wire and terminal are then heated and connected together with solder. This method provides a secure electrical and mechanical connection.
2.Crimping involves using a crimping tool to press a metal sleeve or ferrule onto the exposed conductor of the wire and the corresponding terminal on the connector. This creates a secure connection without soldering. Crimp connections are often used in applications where soldering may be impractical or where repeated connection and disconnection are required.
3.Insulation displacement connection connectors (IDC Connectors)have sharp contacts that pierce the insulation of the wire to establish a connection with the conductor. This method is often used in applications that require quick and tool-free connections, such as certain types of connectors used in telecommunications or data cables.
4.Compression or clamp type connectors are designed to hold the wire securely in place through a compression or clamping mechanism. Insert the wire into the connector and then tighten the screw, clamp, or compression mechanism to create a secure connection.
5.Screw-in connectors usually have a screw-in cap for securing twisted wires. In simpler electrical installations, the wires may be connected to the connector by twisting them together and using a screw-in wire connector.
6.Cable lugs are used for larger wires or cables. These are metal terminals that can be crimped or soldered to the end of the wire to provide a connection point for a larger connector or terminal.
The choice of connection method depends on factors such as the application, the type of connector, the size of the wire, and the level of reliability required.
Wire Specifications and Application Considerations
When selecting wire for a specific application, it is important to ensure that the size and gauge match the connector and the circuit’s electrical needs. Specific areas such as neurostimulation or implantable devices may require the use of microscopic wires with diameters of only microns or less. The gauge number is inversely proportional to the wire diameter, so the larger the gauge number, the smaller the wire. In some cases, the wire may be part of a cable assembly that contains multiple conductors.
Wire flexibility and bending restrictions
Where flexibility is critical, special attention should be paid to the flexibility of the conductor and the minimum bending radius it can withstand without damage should be determined.
Temperature adaptability
The wire should have a temperature rating appropriate for the environment in which it will be used. Consider the temperature of the operating environment as well as the heat that may be generated within the system. In some cases, the wire may also act as a heat sink.
Design and standardization requirements
Wires must meet multiple standards and regulations to ensure the safety, performance and quality of the equipment. This includes UL and CSA standards. In the medical field, it is also necessary to comply with US FDA regulations, EU CE marking (Medical Device Directive or Medical Device Regulation) and EU Medical Device Directive (MDD) or Medical Device Regulation (MDR). Wires in the military or aerospace fields must comply with relevant wire and cable standards such as MIL-W-3861 or MIL-N-46026A.
Sensor wire applications
When using wires in sensors, special attention needs to be paid to ensure accurate signal transmission, reliability of the connection, and overall effectiveness of the sensor system.
Wire Length and Resistance
To reduce resistance and signal loss, wire length should be kept within the recommended range. Long wires will create resistance and affect the accuracy of sensor readings, which is especially important when precise measurements are required.
Signal Hold
To maintain the integrity of the sensor signal, choose wires that have proper shielding and low susceptibility to electromagnetic interference (EMI). Shielded cables help reduce noise and ensure accurate sensor readings.
Stress relief
Proper strain relief should be implemented to avoid mechanical stress at the wire and connector joints. This helps to extend the life of the connection and reduce the risk of wire breakage.
Material selection
The choice of material depends on the specific application, the type of sensor or device connected, and the durability requirements. Copper is a common conductor material, but in some cases, materials such as silver or alloys may be more suitable. In the medical field, biocompatible insulation materials can be used around the wires. The choice of core conductive material is also critical, such as stainless steel, gold, platinum or nickel titanium alloys, which are corrosion-resistant and suitable for applications that may be exposed to humid environments. At the same time, the temperature rating must also be considered, and some wires may have color-coded insulation.
Waterproof seal
To ensure that the wires are not damaged when used with sensors or other components exposed to humid environments, the wires and connectors must have good waterproofing and sealing properties.
Cable Management Strategies
Proper cable management prevents wires from becoming tangled, twisted, or entangled, which is especially important when the sensor is moved or multiple sensors are used.
Application fields and markets
Wires play an important role in the fields of industry, medical, military and aerospace, test and measurement, etc. In the field of medical electronics, wires are crucial in connecting sensors, electrodes and devices to monitoring or treatment equipment. Common medical applications include electrocardiogram (ECG/EKG), electroencephalogram (EEG), electromyogram (EMG), patient monitoring systems, neurostimulation devices, defibrillators and pacemakers.
