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曹伟1993

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As shown in the figure, there is usually a 5V voltage input at the arrow position, and the test pin 1 position outputs a low level. Now the problem is that the input at the arrow position is turned off, but due to the input device, there will be very short inputs (2~3V) at certain times, which will cause the probe position input to also be a low level, resulting in an incorrect judgment. How can we eliminate this false trigger?

qwqwqw2088

Turn off the input at the arrow position, but due to the input device, there will be very short input (2~3V) at some point

Turn off input, reason for input device?

What is the reason? Please tell me.

曹伟1993

qwqwqw2088 posted on 2019-12-25 09:35 Turn off the input at the arrow position, but due to the input device, there will be very short input (2~3V) at certain times. Turn off the input, input setting...

This is a machine being tested. I turned off the machine, which means it is powered off, but sometimes there is still input.

dcexpert

For interference signals, it is necessary to process them according to the signal amplitude, frequency, pulse width, etc.

曹伟1993

dcexpert published on 2019-12-25 09:41 For interference signals, it is necessary to process them according to the amplitude, frequency, pulse width, etc. of the signal

100HZ, 2~3V

qwqwqw2088

Add positive feedback, hysteresis comparator

maychang

The electrical schematic in the first post is a bit strange.

U1A is an ordinary op amp, and the output of the op amp is connected to both the non-inverting input and the inverting input of the op amp. What does this mean?

I suspect there is something wrong with the electrical schematic.

maychang

First, we need to solve the problem of connecting the output of the op amp in the electrical schematic diagram to both the non-inverting input and the inverting input at the same time before we can talk about how to eliminate "false triggering".

chunyang

The circuit in the OP's diagram is wrong. The circuit on the left should provide a 12V reference voltage, but if it is connected as the OP's diagram shows, the output may be uncertain. The connection method of the circuit on the right should be used to distinguish whether the input is in the 11-13V range, while 5V and 2-3V are not in this range. The OP should first clarify the specific application requirements and describe the problem correctly and completely.

曹伟1993

chunyang posted on 2019-12-25 15:35 The circuit in the OP's diagram is wrong. The circuit on the left should provide a 12V reference voltage, but if it is connected as shown in the OP's diagram, the output may be uncertain. The connection method of the circuit on the right is...

It is troublesome because the ones on the right are not in the range. If they are in the range, it will be easy to deal with. There is indeed a problem with the left side. The diagram is wrong, but now I have thought of a solution. Set the interval to 4~6, so that they can be distinguished. Thank you.