Function and 7 Common Types of Solenoid Coil

Function and 7 Common Types of Solenoid Coil?

Close-up of cylindric inductors with helical copper wire winding. Group of electronic components in technical detail. Electromagnetic induction. Electrotechnics

Figure 1: several types of solenoid coil.
(Go to Okmarts and pick the Solenoid coil you need)

1. Function

1.1 Blocking Effect

The self induced electromotive force in the inductance coil always competes with the change of current. The solenoid coil has a blocking effect on AC current. The blocking effect is called inductive reactance XL, and the unit is Ohm. Its relationship with inductance “l" and AC frequency “f" is XL = 2 π fl.

1.2 Tuning and Frequency Selection

The LC tuning circuit is composed of inductance coil and capacitor in parallel. That is, the natural oscillation frequency “f0“ of the circuit is equal to the frequency “f" of the non AC signal. At this time, the inductive reactance and capacitive reactance of the circuit are also equal, so the electromagnetic energy oscillates back and forth in the inductance and capacitance. During resonance, the inductive reactance and capacitive reactance are equivalent and reverse. The inductive reactance of the total circuit current is the smallest and the current is the largest (referring to the AC signal of “f" = "f0"). LC resonance circuit has the function of selecting frequency and can select the AC signal of a certain frequency "f".

2. 7 Common Types of Solenoid Coil

2.1 Single Layer Coil

Figure 2: Single layer coil.

The single layer coil is wound on the paper barrel or bakelite frame with insulated wires . Such as medium wave antenna coil of transistor radio.

2.2 Honeycomb Coil

Figure 3: Honeycomb coil.

If the plane of the wound coil is not parallel to the rotating surface, but intersects at a certain angle, this kind of coil is called honeycomb coil. The advantages of honeycomb winding method are small volume, small distributed capacitance and large inductance. Honeycomb coils are wound by honeycomb winding machine. The more folding points, the smaller the distributed capacitance.

2.3 Ferrite Core Coil and Iron Powder Core Coil

Figure 4: Ferrite core coil.

The inductance of the coil is related to whether there is a magnetic core or not. Inserting a ferrite core into the air core coil can increase the inductance and improve the quality of the coil.

2.4 Copper Core Coil

Copper coil switch in the hands of a master

Figure 5: Copper core coil.

Copper core coil is widely used in ultrashort wave. Rotating the position of copper core coil to change the inductance is more convenient and durable.

2.5 Color Code Coil

Color code coil is an coil with fixed inductance, and its inductance is marked by color ring like resistance.

2.6 Choke Coil

Closeup of electronic components. Coils or electrolytic capacitors on PCB detail of DC-DC converter

Figure 6: Choke coils.

The coil limiting the passage of alternating current is called the choke coil, which is divided into high-frequency choke coil and low-frequency choke coil.

2.7 Deflection Coil

The deflection coil is the load of the output stage of the TV scanning circuit. The characteristics of deflection coil are high deflection sensitivity, uniform magnetic field, small volume and low price.