VCC: Power supply pin, connected to the positive power supply, usually 3V or 5V. GND: Ground pin that connects the negative power supply to the common ground of the circuit. SCL: Clock line pin, used to control the clock signal of data transmission. SDA: Data cable pin for data transmission. A0: Address bit selection pin that selects different device addresses by setting high or low levels.
Measuring voltage First we need to prepare a multimeter, and then set the multimeter to zero, so that the error can be minimized, and then set the multimeter to DC voltage to indicate that the measurement is DC voltage. Some voltmeters do>
Confirm chip pin function: First, you need to check the data manual of the chip to confirm the function of each pin. Digital logic chips usually have input pins, output pins, power pins, ground pins, etc. Make sure you understand what each pin does and how it connects. Choose the right package: Depending on the chip model you are using and the design of the board, choose the right chip package.
Confirm connection: After connecting the logic chip, you need to carefully check whether the connection is correct. Test tools such as multimeters can be used to check parameters such as voltage, current, and signal in the circuit to ensure that the circuit is not connectedBad.
According to the requirements of digital logic circuit diagram, find the chip that needs to be connected. According to the function and number of the chip pins, find the pins that need to be connected on the circuit diagram. Using a wire to connect the pin of the chip, usually need to pay attention to two aspects: first, the connected wire should be long enough and thin enough to ensure that it can be connected to the correct position; The second is that the connected wire should be strong enough to avoid problems such as poor contact.
The input and output need to be properly connected, and the output signal needs to be connected to the input for processing. The pin of the chip needs to correspond to the symbol on the circuit diagram,To ensure proper connection. The chip connection should follow the direction of the signal stream, i.e. from the input end to the output end. The connection mode needs to meet the design requirements of the circuit diagram to ensure the correctness and reliability of the circuit.
The input side needs to be connected to the input signal, and the level of the input side needs to be stable, free from interference from other signals. The output end needs to be connected to the load circuit to achieve the output function, while paying attention to the level of the output end needs to remain stable and not be interfered by other signals. In the chip, it is necessary to connect a number of logic gate circuits to make it operate according to the correct logical relationship, so as to achieve the correctLogical function.
1, obviously not bad digital multimeter chip , is the battery voltage is insufficient digital multimeter chip , change the battery try.
2, the table digital multimeter chip core chip is ICL7106, soDon't worry too much about the price. Digital multimeter overvoltage damage is more difficult to deal with, see digital multimeter chip your watch internal work is really good, and 7106 chip or DIP package, ha ha, so it is still saved.
3, if the DC AC voltage and current files appear -1 and battery ICONS, the measurement appears garbled, that is A/D conversion chip has been broken, the digital multimeter commonly used A/D conversion chip is 7106. If the battery is out of power, it will only appear the battery icon and measurement is not accurate, not garbled, and not in the no-1 appears when the value of -1 is -1.
4, if the digital display multimeter all gear boot shows -1, it is the main chip burned. You can try to change the battery, or check the fuse, which is usually hidden in the battery compartment. -1 keeps flashing, this situation is that the 9V stacked battery in the table is insufficient, warning that the battery needs to be replaced, and the measurement value is inaccurate and large.
5, it is likely that there is a problem with the computing integration block, and various functions are finally realized in the form of voltage measurement, so it may also be a problem with the voltage divider.
6, if the multimeter is goodThere are the following situations. The range of the multimeter is incorrect, and the range is lower than the battery voltage Digital multimeter chip ; Watch pen red, black insert reverse, negative; The message "HOLD" is displayed on the screen. Press this key to release the lock.
If DC AC piezoelectricStream file and so on appear -1 and battery ICONS, the measurement appears garbled, it is A/D conversion chip has been broken, the digital multimeter commonly used A/D conversion chip is 7106. If the battery is out of power, it will only appear the battery icon and the measurement is inaccurate, will not be garbled, and will not appear -1 when the value is not -1.
Old multimeter Mechanical pointer multimeters out of use for many years are estimated to have at least a problem connecting the battery line. Remove the battery cover and check whether the connection between the two batteries is abnormal. Open the back cover to check the internal components, solder, rotary switch under visual inspection, rotation. The battery is only used to measure resistance, to measure voltageCurrent capacitance is not required.
Use a multimeter to measure the resistance, the reason for the resistance value of 0 May be: (1) The resistance is short-circuited, similar to a small resistance, almost 0 wire, so the resistance value is 0. (2) The range selection is large, assuming that the resistance value we measure is several ohms, choose the gear of kΩ, there will be no digital display, which is also 0.
Measuring the current is the most likely to burn the multimeter operation, it is very likely that the current you are measuring exceeds the allowable value of the table. If we're lucky, the safety inside may have burned out, which is a relatively easy fault to deal with. If you burn the watch, it's numbBored.
1, the back of the chip (printing side) face up, the notch (or a vertical line) left, then the first foot in the bottom left is 1 foot, and then in the counterclockwise direction is 4...... Legs; If there is a small concave point, the foot facing the small concave point is 1 foot, and then the foot counterclockwise is 4. Legs.
2, the first step of the test is to determine which pin is the base. At this time, we can take two electrodes (such as these two electrodes 2) and use two multipurpose metersThe pen is reversed to measure its positive and reverse resistance and observe the deflection Angle of the watch hand; Then, take 3 two electrodes and 3 two electrodes, respectively, inversely measure their positive and reverse resistance, and observe the deflection Angle of the watch hand.
3, put the multimeter in resistance X1k stop, assuming that a certain pin of a receiving head is the ground pin, and the black watch pen is connected, and the red watch pen is used to measure the resistance of the other two pins. 2, and then compare the size of the resistance value measured twice, generally in the range of 4 ~ 7k, the smaller resistance of the red pen connected to the 5v power pin. 3, the other foot with a larger resistance value is the signal foot.
4, the method is very simple, the user can connect a 0.24 ohm resistance between the "5A" jack and the black watch pen jack, so that the gear becomes a 5A current stop. The connected 0.24A resistor should be selected to use a wire-wound resistor above 2W, if the power is too small, it will burn out. ? Use a multimeter to determine the positive and negative poles of the speaker First, dial the pointer multimeter to the DC 0 ~ 5mA gear, and then connect the two meter pens to the two solder pads of the speaker to be tested.
5, the receiving head manufacturer Guo Wei for you to solve the receiving head foot identification method is as follows: First prepare a 5V power supply,Because the normal working voltage of the three-end infrared receiver is 5V (it can also be replaced by a 3V power supply composed of two batteries).