ls248 is a 4-wire seven-segment decoder driver BCD inputIn, there is a pull-up resistor, 248 is a BCD seven-segment decoder/driver with an internal pull-up resistor, a total of 5474248 and 5474LS248 two line structure types.
LS192 is a dual clock, can be preset number, asynchronous reset, decimal (BCD code) reversible counter, also can choose 54HC192, 54HCT192, 74HC192, 74HCT192 and so on.
LS11: TTL 3 Input 3 and gate 74LS48: TTL BCD - 7-segment decoding/boost output driver 74LS148: TTL eight-wire three-wire priority encoder 74LS192: TTL preset BCD dual-clock reversible counter 74LS2279: This chip does not seem to oh, I guess you are wrong.
segment decoding function (LT = 1, RBI = 1) When the lamp test input (LT) and dynamic zero out input (RBI) are both connected to invalid power, the input DCBA is decoded by 7448, and the output of the high level active 7-segment character display is drivenDynamic signal, display corresponding character. In addition to DCBA = 0000, RBI can also be connected to low levels, as shown in Table 1 Lines 1 to 16.
L stands for low logic level. X= irrelevant. Look at the internal logic diagram to better understand what's going on. Know exactly how the logic implements the function. EI is input, no judgment required. It's a control signal. When EI is high, no encoding is required, and all 5 outputs are high. EO is the "or not" relationship of each input signal. EO is low when all inputs are high. Otherwise, EO is high.
LS148 is a device with8-wire to 3-wire priority encoder with extended function, a total of 54/74148 and 54/74LS148 two line structure types, it has 8 signal input, 3 binary code output, an enable end, a gate output end and an expansion end. In terms of function, 74LS148 performs 3-wire (4-2-1) binary priority encoding for 8 data lines (0-7), that is, decoding for the highest bit data line.
a) Circuit function: first, the number of the answer player is identified and locked to display on the digital tube, and the second is to make other players' buttons invalid; Three is someone robbedOutput timing control signal to make the counting circuit stop working and alarm.
1, first of all led nixie driver chip You have to know led nixie driver chip , each nixie this 8 section is equivalent to a light-emitting diode LED, the working current is up and down 5mA. To drive this LED, rely on single-chip IO direct output definitely not. LED drive general low power plastic sealThe operating current of the transistor (9018550, 2N3906, etc.) is greater than 5mA, so it can definitely work.
2, the principle of the nixie drive circuit is to use a signal called segment selection, select the digital segment to be displayed, and provide current for the digital segment, so that it lights up. Then, using a signal called bit selection, select the numbers displayed and provide an electric current to the digital segments of the selected numbers, causing them to light up. The nib drive circuit is usually composed of two parts: segment selection circuit and bit selection circuit.
3, connection: the 74HC595 chip pinConnected to the digital tube, including serial input, clock input, parallel output and output enable pins. Data transmission: The single chip computer will convert the displayed numbers into binary data, and input the serial input pin to the 74HC595 chip. Shift operation: Clock input pin clock signal, so that the input binary data inside the 74HC595 chip for shift operation.
4, it is composed of three pole control transistors, respectively PNP type and NPN type. It can control the display of the digital tube by controlling the current between the electrodes. When using the 9012 triode to drive the niticon, you need to set oneKey wake up.
Alas. Change the circuit board. Add a switch, 340 has been power supply, the switch is used to control the MCU power supply. However, it is said that there is also a power-free download method, that is, to change the upper computer, can not use the isp software stc. Have always wanted to study it, but there is not so much time online there are a lot of power-free download methods, the owner can search.
You have to figure out the meaning of power-on reset, taking the single chip microcomputer as an example: the reset circuit is composed of two parts, capacitance and resistance. When the system is powered on, the voltage on the VCC changes from zero to RESETIt will first be at a high level for a period of time, and then because the point is grounded through the resistance, the level of the RESET point will gradually change to a low level, so that the level of the reset port of the single-chip microcomputer will be from 1 to 0, to achieve the reset function of the single-chip microcomputer.
1, HC595led digital tube driver chip , 74LS165, etc. According to the query, 3 digit digital tube led digital tube driver chip The driver chips commonly used are 74HC595, 74LS165, 74Ls164, TM1617 and so on. When using 74HC595, each segment should add a series resistor, and pay attention to whether the refresh frequency is too low when programming, otherwise it will produce obvious blinking phenomenon.
2, TM1617 can, there are LED nixie driver IC selection table and a full set of specifications for everyone to download, reference selection table can be their own selection of led nixie driver chip . I hope it helps.
3, if noIf you guess wrong, this is the digital voltmeter head product of Yuanbo Electronics. According to the company's personnel reply led digital tube driver chip : This chip is a specially customized MCU of the company, which cannot be purchased on the market, but can be ordered by mail from the company at express costs.
hcf4511be is 4-wire - seven-segment latch, decoder/driver. The 4-line BCD code is latched, translated into seven-segment code, and the driver outputsSeven segments display signal.
hcf4511be performance: Version hcf4511be camera can be high-definition, standard definition, automatic mode viewing. In automatic mode, the stream adaptive technology can automatically match the most suitable mode according to the network condition.
CD4511BD, CC4511BD is BCD-- 7 segment latch/decode/driver, input 4 lines, can input 4 lines of BCD value, after the latch (or direct input) decode output as a numerical segment signal, output segment signal, can directly drive LED digital.