1, the foot identification method is, the chip identification, model inOn, placed on the desktop, the first foot of the positioning port is the 1 foot of the chip, the number of counterclockwise 4, and then the opposite of the 4 foot is the 8 foot. Pin 1 of the chip is the compensation end, pin 2 is the feedback end, pin 3 is the overcurrent detection end, pin 4 is the RC clock end, pin 5 is the power supply end, pin 6 is the control output end, pin 7 is the positive end of the power supply, pin 8 is the reference voltage end.
2, double in-line IC pin sorting according to the counterclockwise direction, 1 pin in the IC identification dot (or gap) left.
3. The patch 8-pin integrated circuit uc3842 has the foot of the small garden pit as the first foot. Switching power supply only power tubeA breakdown? Usually a 3842 is destroyed.
4, generally between 10-30V. 7 is the power pin, and 20v is normal. In general, directly change a 3842, to ensure that the mos does not break down, disconnect the gate, power, multimeter test 3842 pin 6 swing voltage is basically okay.
5, first of all, we should determine whether the main control chip UC3842 of the charger is in the working state or has been damaged. The judgment method is as follows: Power on to measure the 7th pin to ground voltage of UC3842, if the 8th pin has 5V voltage, pin 1,2,4,6 also has itDifferent voltages indicate that the circuit has vibrated, and UC3842 is basically normal; If pin 7 has low voltage and other pins have no voltage or fluctuation, the UC3842 is damaged.
6, whether the switching power tube breakdown damage, UC3842 and the surrounding components are broken, burned, etc., if the components are damaged, you can replace them, no DC voltage output, but the safety wire is intact: First judge whether the charger's control chip UC3842 is in a Wang state or has been damaged. If these feet are not broken down, and the charger still cannot start normally, it also indicates that the UC3842 has been damaged and should be replaced directlyWhat is a chip? No word _ Baidu... '>utc3842 and lm358 chargers,358 with an octa chip next to what? No word _ Baidu...
A lot of charger online search information, the principle is much the same, the general power chip, comparator, optocoupler chip, there are different combinations, the schematic diagram is also introduced, the chip is polished, there is no way to identify.
The role of the foot integrated block should be to generate the switch tube drive signal, 358 is to control the charging mode and the battery saturation state detection. Electric car charger is specially configured for electric bicycle batteriesA charging device! Classification of chargers: with and without power frequency (50 Hz) transformers, can be divided into two categories.
Your circuit board is not a charger, it is a switching power supply, that is, an AC to DC circuit board. There are many kinds of circuits, and different types of integrated blocks on the upper 8 pins are different. For example, UC384LM358. It's labeled on it. Look at it.
LM358 is a dual op-amp, its pin is very simple: 3 pin is an op-amp channel, 1 pin is the output, 2 pin is the inverting input, 3 pin is the in-phase input; 7 Feet for the other luckPut the channel, 7 pin is the output end, 6 pin is the inverting input end, 5 pin is the in-phase input end; 8 pin is a positive power supply; 4 pin is negative power supply (dual power supply working) or ground (single power supply working).
SP130H1 is a single chip microcomputer PIC12F675, and some are identified as PD532A or KAPC4L139.
1, the working conditions, 7 pin voltage "15 volts to start, 4 pin will have 1 volt pulse triangle wave signal.
2, C3 should be connected to the left end of R9 and the ground, the compensation network from pin 1 to pin 2 can not cut off the DC, that is, there should be a direct crossover resistance between pin 2.
3, modify the error, which will completely destroy the isolation effect of the switching transformer, so that the output end with 220V high voltage, is a fatal defect. In order to feedback from the output, an optocoupler isolation circuit must be designed.
1, the P3482 on Skyworth LCD color TV is a power management integrated block. A P3482 is an EUP3482. The function of each foot: the first pin BS is the potential pull height foot; Add a 10nF capacitor between BS and SW; The second pin IN is the input voltage supply pin; The third pin SW is the output pin of the switch; The fourth pin GND is ground level; The fifth pin FB is the feedback input end; The sixth pin COMP is the compensation pin of the control circuit.
2, /Its 3482 chip circuit diagram His check method: Exclude p3482 Skyworth chip peripheral components without short circuit chip circuit diagram , first check the main power supply VIN< /strong> chip circuit diagram , If the VIN is normal 3482 chip circuit diagram , lift the LDO foot to check whether the LDO is normal, no LDO indicates that the chip has been damaged; If further verification is needed,Then check whether VCC is normal, and note that the chip itself can be damaged even if there is no REF.
3, p component refers to a class of electronic components with p marked components, usually refers to the amplifier or switching characteristics of the diode, transistor or field effect tube. p refers to positive materials, corresponding to N-type materials. p element has good control performance and amplification characteristics, and plays a crucial role in the design and manufacture of electronic circuits.
4, if it is P, it is generally insurance, check whether it is disconnected, if it is straight through, it is normal.
5, no matter the kind of power supply, its structure is much simpler than the power supply of the crt display, and the vulnerable components are generally some small components, such as safety tubes and rectification Bridges. Power board commonly used ic: 6841203d06, these commonly used pmw chips in my professional LCD accessories store can be bought.