The output voltage of 74ls192 is too large

志行天

The output voltage of 74ls192 is too large [Copy link]

The output of 74ls192 is 5V when it is low level and 10V when it is high level. What is the problem? Please help me solve it.

maychang

The power supply voltage of this chip is 5V, so it is impossible to output 10V. If a 10V voltage is measured at the chip output, it must be caused by external factors and the chip is damaged.

志行天

Is it because the voltage applied is too high?

志行天

maychang published on 2020-11-8 11:14 The power supply voltage of this model chip is 5V, and it is impossible to output 10V. If a 10V voltage is measured at the output end of the chip, it must be caused by external reasons, and the chip...

Is it because the voltage applied is too high and it burns out? It will not output 0 voltage

maychang

Zhi Xingtian published on 2020-11-8 12:39 Is it because the voltage applied is too high and it burned out? It will not output 0 voltage

"Is it because the voltage applied is too high and it burned out? It will not output 0 voltage."

I don't know if you mean the power supply voltage or the input voltage when you say "the voltage applied is too high". Whether the power supply voltage or the input voltage is too high, it may damage the chip. However, whether the power supply voltage or the input voltage is too high, the chip will not output 10V.

maychang

Zhi Xingtian published on 2020-11-8 12:39 Is it because the voltage applied is too high and it burned out? It will not output 0 voltage

If the chip is damaged, it will usually get hot or even smoke. First, touch the chip to see if it is hot.

In addition, the first post says "5V when outputting low level, 10V when outputting high level", which is rather strange. It is very likely that the chip is not damaged, because it can still output high and low levels. It is suspected that there is a resistor in series with the chip output end, and you measured the voltage at the end where the resistor is not connected to the chip output end. Another possibility is that you measured the voltage incorrectly.

maychang

Zhi Xingtian published on 2020-11-8 12:39 Is it because the voltage applied is too high and it burned out? It will not output 0 voltage

74LS192 is a BCD counter with a power supply voltage of 5 V. Under normal circumstances, the high level output of this chip cannot reach 5 V, and the typical value is only 3.5 V (unless a pull-up resistor is added to the output end to reach above 4 V).

chunyang

Output 10V? What's the power supply voltage? If the power supply voltage is much higher than 5V, the components on the board may have been destroyed long ago, and there is a high possibility of smoke and explosion. If it is not a power supply voltage problem, first measure the voltage of an ordinary dry cell to see if the meter reading you use is reliable?

qwqwqw2088

The measurement error wouldn't be that big.

The high level exceeds the supply voltage by so much

one-old-man

Where is the reference point? GND or Common point