Tool/software:
First of all, hello. First of all, I had a problem with the circuit I made and wanted to get your opinions. I cannot get the resistance values I planned. After soldering a 1M resistor to any PCB using flux with a soldering iron, its value decreases. This decrease in value starts when I first put it on and decreases significantly within 5 minutes. And the resistance values are not stable, sometimes increasing and sometimes decreasing. Is the problem with my PCBs? Because when I connected the resistor to the cable instead of the PCB, its value decreased. As I added in the attachment, I use 6 pieces of 1M ohm resistors in the circuit. What they all have in common is that they are connected to a 5 volt voltage regulator. Normally, if the resistors appear to be 1M, 5 volts come out of the resistor in a very healthy way. However, the 1M resistors I put seem low. Although some may seem like 1M, some give values like 100k-300k. In this case, 5 Volts entering from one end of the resistor drops to the range of 1-3 Volts when it exits the resistor. (If there is a 1M ohm floating resistor, things work normally. I tried to explain the situation as clearly as possible in the photos I added. I ask for your help and advice. What could be the reason for this situation and what can be done?) you propose to solve this situation.
