Sampling resistance features

Two sampling resistor is connected in series, resistance is generally of the order of magnitude of k Ω;

Its two ends are usually connected to the low voltage output of the power supply;

The intermediate connection point is usually connected with the amplifier element.

The profile of these two resistors, the accuracy and other resistors are probably a little different.

Once you have identified the "sampling resistance", you can prepare an additional resistor 5-10 times larger than it, preferably in parallel with the sampling resistance connected to the voltage positive electrode.

When the l is connected, it is charged, and the output voltage is recorded with the digital table, which is compared with the original output voltage of the charger. If there's a change, then congratulations, you've got the right resistance. Reconnect the resistance with an appropriate resistance value to get the voltage you need.

However, please note: there should be no problem in lowering the voltage. If you want to make it higher, you don't want to make it higher. Because the charger is a switching power source, the circuit works on the flyback, and the higher the output voltage, the higher the backpressure the switch experiences. Therefore, if the output voltage is changed too high, it is possible to break the switching tube due to overvoltage!!!

So it might be enough to increase the output voltage by 20%, which means that a 5V charger can be changed to about 6V.

There is no amplifying element and sampling resistance, only one stabilizer for voltage standard. The output voltage can be changed by changing this stabilizer to different voltage values.