JPH0229699Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power transformer used in electrical equipment such as audio equipment, and particularly relates to an improvement of a power transformer that can accept multiple types of voltage input.

Conventionally, especially in audio equipment and the like whose power supply transformers can handle multiple types of input voltages, if pulse noise is mixed in the power supply, it is amplified and generates noise. Conventionally,
A power transformer used in audio equipment, etc. that can input multiple types of voltage, for example 110V.
In a power transformer that can apply a power supply voltage of 220V, first install a 0V tap on the bobbin made of insulator, start winding the primary winding,
The 110V tap was taken out at about half of the total number of turns, and the 220V tap was taken out from the end of the primary winding. After an insulator is wound around the outer periphery of the primary winding, the secondary winding is wound. For this reason, in the above conventional power transformer, when a power supply is connected between the 0V tap and the 100V tap, the power is mixed into the power supply from the 220V tap located close to the secondary winding. There is a drawback that the noise is induced on the secondary side through the stray capacitance generated between the primary winding and the secondary winding, and the noise is mixed into the circuit of the device.

The present invention aims to eliminate the above-mentioned conventional drawbacks, and provides a power transformer that can reduce the amount of noise mixed in.

The present invention will be explained below with reference to the embodiments shown in FIGS. 1 and 2. First, install the 220V tap 2 on the bobbin 1 made of insulator, start winding the primary winding 3.3', take out the 110V tap 4 at about half of the total number of turns, and then take out the 110V tap 4. Take out the 0V tap 5 from the end of the next winding 3.3'. After the insulator 6 is wound around the outer periphery of the primary winding 3, 3', the secondary winding 7 is wound. Therefore, in the above power transformer 8, when a power supply is connected between tap 5 for 0V and tap 4 for 110V, the distance between tap 2 for 220V, which is not used, and the next winding 7 increases.
1 because the primary winding 3' for 110V is shielded.
Stray capacitance occurring between the secondary winding 3, 3' and the secondary winding 7 can be reduced. Therefore, the noise transmitted to the secondary side through this stray capacitance can be reduced.

As described above, the present invention involves winding the primary winding around the bobbin from the high voltage side, providing a tap for high voltage at the starting end of the primary winding, and a tap for 0 volt at the terminal end. , a low-voltage tap is provided at the midpoint of the primary winding, and the secondary winding is wound around the outer periphery of the primary winding with an insulator interposed therebetween. When a power supply is connected between the high voltage tap and the low voltage tap, the distance between the unused high voltage tap and the secondary winding increases, and the low voltage winding is shielded, so the primary Stray capacitance occurring between the winding and the secondary winding can be reduced.

As a result, noise that enters the power supply from the high voltage tap and is transmitted to the secondary side through the stray capacitance can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional front view of a power transformer according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a power transformer according to an embodiment of the present invention. 1...Bobbin, 3.3'...Primary winding, 4...
...Tap, 8...Trance.

Claims (1)

[Claims for Utility Model Registration] In a power transformer having a tap in the middle of the winding so that at least two different power supply voltages can be input, the primary winding is wound around the bobbin from the high voltage side, and the above-mentioned 1. A high voltage tap is provided at the starting end of the secondary winding, a 0 volt tap is provided at the terminal end, and a low voltage tap is provided at the midpoint of the primary winding, and A power transformer characterized by having a secondary winding wound around the outer periphery of the wire with an insulator interposed therebetween.