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pin discharge

pin discharge

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Product Description

The impact of pin discharge on personal safety is mainly reflected in the following aspects:

1. Mechanical hazards:

If the pin design of the plug is unreasonable, or the weight of the product is too large or the center of gravity is inappropriate, the product may accidentally fall off the wall, and the pin may scratch the body or puncture vulnerable parts such as the face and feet. In extreme cases, if the latch falls vertically onto a child's head, it may be life-threatening.

2. Electrical hazards:

When the power plug is connected to an AC power supply, the X capacitor in the electronic device is connected to the power supply. The voltage on the X capacitor is synchronized with the power supply and changes sinusoidally. Therefore, the remaining voltage on the power plug is related to the timing of unplugging the power plug. . If the power plug is unplugged at period 0 and 1/2T or T time, the remaining voltage is 0. If the power plug is unplugged at 1/4T time or 3/4T time, the residual voltage is the largest, which is Um or -Um respectively. After unplugging the power plug, there will be a residual voltage on the plug within a certain period of time. According to the GB9706.1 standard, in the first second after disconnecting the plug, the voltage between the plug's pins and the device's case should not exceed 60V, or the Discharge energy should not be greater than 2 millijoules, which can be considered safe for humans.

3. Remaining energy:

Due to the improper selection of the X capacitor capacity and the lack of a reasonable discharge circuit, when the user unplugs the device power plug and accidentally touches the plug pin, the remaining energy stored in the X capacitor may cause an electric shock to the user. Human body impedance usually includes external impedance (related to the clothes, shoes and socks worn at the time of the electric shock, and the moisture content of the body, ranging from several thousand ohms to tens of megohms) and internal impedance (related to the skin impedance and body impedance of the person who received the electric shock) ), human body impedance is not pure resistance, it is mainly determined by human body resistance. Human body resistance is not a fixed value either.

4. Discharge time constant:

Different standards have different basis for determining whether the equipment under test meets the standard requirements, but generally the following two parameters are examined. One is to examine the voltage at a specific time to determine whether it meets the voltage value specified by the standard, such as GB4706.1-2005 ( IEC60335-1:2010) stipulates that when the test sample is disconnected from the power supply at the voltage peak, the voltage between each pin of the plug shall not exceed 34V 1s after disconnection; the second is the difficulty encountered in monitoring work. Examine the time required for the voltage to drop to a specific value and determine whether the time is shorter than the time required by the standard. For example, GB4943.1-2011 (IEC60950-1:2013) requires the discharge time constant of type A pluggable equipment. No more than 1s. For type B pluggable equipment, the discharge time constant does not exceed 10s. The discharge time constant is defined as the period of time during which the discharge voltage will decay to 37% of the initial value.

In general, the impact of pin discharge on personal safety mainly depends on factors such as plug design, product usage, and environmental conditions. These factors should be fully considered when designing and using electronic products to ensure user safety

Products Details

Home > Products >
Certification
>
pin discharge

pin discharge

Detail Information
Product Description

The impact of pin discharge on personal safety is mainly reflected in the following aspects:

1. Mechanical hazards:

If the pin design of the plug is unreasonable, or the weight of the product is too large or the center of gravity is inappropriate, the product may accidentally fall off the wall, and the pin may scratch the body or puncture vulnerable parts such as the face and feet. In extreme cases, if the latch falls vertically onto a child's head, it may be life-threatening.

2. Electrical hazards:

When the power plug is connected to an AC power supply, the X capacitor in the electronic device is connected to the power supply. The voltage on the X capacitor is synchronized with the power supply and changes sinusoidally. Therefore, the remaining voltage on the power plug is related to the timing of unplugging the power plug. . If the power plug is unplugged at period 0 and 1/2T or T time, the remaining voltage is 0. If the power plug is unplugged at 1/4T time or 3/4T time, the residual voltage is the largest, which is Um or -Um respectively. After unplugging the power plug, there will be a residual voltage on the plug within a certain period of time. According to the GB9706.1 standard, in the first second after disconnecting the plug, the voltage between the plug's pins and the device's case should not exceed 60V, or the Discharge energy should not be greater than 2 millijoules, which can be considered safe for humans.

3. Remaining energy:

Due to the improper selection of the X capacitor capacity and the lack of a reasonable discharge circuit, when the user unplugs the device power plug and accidentally touches the plug pin, the remaining energy stored in the X capacitor may cause an electric shock to the user. Human body impedance usually includes external impedance (related to the clothes, shoes and socks worn at the time of the electric shock, and the moisture content of the body, ranging from several thousand ohms to tens of megohms) and internal impedance (related to the skin impedance and body impedance of the person who received the electric shock) ), human body impedance is not pure resistance, it is mainly determined by human body resistance. Human body resistance is not a fixed value either.

4. Discharge time constant:

Different standards have different basis for determining whether the equipment under test meets the standard requirements, but generally the following two parameters are examined. One is to examine the voltage at a specific time to determine whether it meets the voltage value specified by the standard, such as GB4706.1-2005 ( IEC60335-1:2010) stipulates that when the test sample is disconnected from the power supply at the voltage peak, the voltage between each pin of the plug shall not exceed 34V 1s after disconnection; the second is the difficulty encountered in monitoring work. Examine the time required for the voltage to drop to a specific value and determine whether the time is shorter than the time required by the standard. For example, GB4943.1-2011 (IEC60950-1:2013) requires the discharge time constant of type A pluggable equipment. No more than 1s. For type B pluggable equipment, the discharge time constant does not exceed 10s. The discharge time constant is defined as the period of time during which the discharge voltage will decay to 37% of the initial value.

In general, the impact of pin discharge on personal safety mainly depends on factors such as plug design, product usage, and environmental conditions. These factors should be fully considered when designing and using electronic products to ensure user safety