Features and Functions of Transformers

Transformers are common components, including power transformers, audio transformers, intermediate frequency transformers and high frequency transformers. The products are of different types, and their functional characteristics, functions and uses are also different.

Ⅰ. The characteristics of the transformer:

The characteristic of the transformer is to transmit alternating current and isolate direct current, and can realize voltage transformation, impedance transformation and phase transformation at the same time. The windings of the transformer are not connected to each other, but alternating current can be transmitted through magnetic field coupling. The transformer has the function of phase change. By changing the connection of the transformer windings, the voltage signal can be easily inverted.

Ⅱ. The role of the transformer:

The role of the transformer is voltage transformation, impedance transformation and phase transformation. The magnitude of the secondary voltage of the transformer depends on the turns ratio of the secondary to the primary winding. The ratio of the secondary voltage to the primary voltage at no load is equal to the ratio of the secondary winding to the primary winding.

 The transformer also has the function of impedance transformation. The transformer has a different turns ratio between the primary and secondary windings, and the coupled impedance is also different. In terms of value, the ratio of the secondary impedance to the primary impedance is equal to the number of turns of the secondary winding and the turns of the primary winding. The square of the ratio of the number of turns. 

1. Features and functions of power transformers:

The power transformer is the most commonly used type of transformer. It can be divided into step-down transformers, step-up transformers, isolation transformers, multi-winding transformers, etc.; the purpose of the power transformer is to transform the power supply voltage, and can provide multiple power supply voltages at the same time to meet the needs of the circuit.

2. Features and functions of audio transformers:

The audio transformer is a transformer that works in the audio range, and the input transformer and output transformer in the power amplifier are both audio transformers. The audio transformer has the function of signal transmission and distribution. The input transformer transmits the signal voltage and distributes it to transistors VT1 and VT2 (the signal is inverted when sent to VT2) so that VT1 and VT2 will amplify the positive and negative half-cycle signals in turn, and then the output transformer will combine the signals for output. The audio transformer has the function of impedance matching. The output transformer transforms the low impedance of the speaker into a high impedance of hundreds of ohms, which matches the output impedance of the amplifier, so that the audio power output by the amplifier is the largest and the distortion is the smallest.

3. Features and functions of intermediate frequency transformers:

The intermediate frequency transformer is habitually referred to as the intermediate frequency transformer, and is used in the intermediate frequency amplifier circuit of superheterodyne radios and televisions. IF transformers are divided into two types: single-tuned and double-tuned. Single-tuned primary, the secondary winding is wound on a magnetic core. The double-tuning type is divided into two independent coils once and twice, which rely on capacitance or inductance for coupling. The intermediate frequency transformer has the function of frequency selection. And coupling

4. The characteristics and functions of high frequency transformers:

High-frequency transformers usually refer to transformers that work in the radio frequency range. The high frequency transformer has a coupling effect. The magnetic antenna of the radio is a high-frequency transformer. The primary winding of the magnetic antenna and the variable capacitor form a frequency selection loop. The selected radio signal passes through the primary winding and the coupling between the secondary windings is transmitted to the high-amp or variable-frequency transistor. The high frequency transformer has the function of impedance transformation. The TV antenna impedance converter is also a high-frequency transformer. The balanced signal output by the folded dipole antenna is transformed into an unbalanced signal through the high-frequency transformer and sent to the TV.