Although the surface Li+ battery has occupied the entire portable world, the NiMH battery has not been completely abandoned. Surprisingly, despite the large difference in energy per unit weight, the energy per unit volume is only about 15% lower than that of Li+ batteries. The biggest disadvantage of NiMH batteries is the high self-discharge rate. The hybrid NiMH battery solves this problem to a large extent, such as the SANYO? Eneloop? battery, which still retains 85% of its power after the next year. The appeal of NiMH batteries is low cost, high security, and easy user replacement. At least standard batteries have these advantages.
The portable device is powered by an AA-size NiMH battery as shown, charging with USB. The charger has a switching frequency of approximately 150 kHz and a battery charging current of 1.1 A (typical AA NiMH batteries at approximately 0.5 ° C). Since the buck converter converts 5V, 500mA into 1.5V, 1.1A when the battery is charged, the current supplied by the circuit to the battery (1.1A) is greater than the current obtained from the USB interface (500mA). It should be noted that since the charging termination cannot be correctly judged at a low charging rate, charging can only be performed with a port of 500 mA or more. Therefore, charging should not be activated when the enumeration determines that only 100 mA of current is available. The system stops the charging by turning off the Q2 on the TMR and leaving the timer resistor floating.
Another particularly useful feature of the charger is to determine if the battery is connected to an alkaline or faulty battery by detecting the impedance of the battery. When this condition is detected, charging will be disabled. This allows the user to insert an alkaline battery in an emergency without worrying about accidental charging.
Our company`s current transformers have high precision,wide range,small volume and good linearity that can be used to the field of electronic watt-hour meter, electric energy metering, electronic detection.
Performance
â—Power frequency insulation strength:The insulation between the primary winding and the secondary winding and the ground part of the CT can bear 4kV power frequency voltage for 1minute
â—Interturn insulation strength:The secondary open circuit, the primary winding through the rated current 1min, no inter-turn damage in the transformer
â—The deviation is better than the industry standards and national standards
Relay Protection Ct,Measurement Ct,Low Cost Current Transformer,Best Precision Ct,Good Ct,Cheap Ct
Anyang Kayo Amorphous Technology Co.,Ltd. , https://www.kayoamotech.com