I wrote the code according to the example in Chapter 7 of "Evc Advanced Programming and Example Development Technology", but I can see that a database file is created, but after I add information on t
A matrix keyboard detection and display program, when a key is pressed, it will be displayed on the LCD and the buzzer will sound. After my program runs, the buzzer keeps beeping. I would like some ad
See the attached figure for the circuit. The input signal is a 5V, 4-20mA signal given by the computer. I need to control the relay, so I added an amplifier circuit in front of the relay. Can you expe