Hello Everybody!
I have probem with measuring some voltage sources which were chargers of various electronic equipments (for example beard trimmer, mobile phones).
I have exactly 3 chargers and have problem with 2. Each have an own characteristic table which clearly says how much voltage can you use with and how much voltage does it produce (with the current value as well).
Let me call the three charger first, second and third.
The first charger made me surprise. It's table says:
PRI: 220-240V 50-60Hz, SEC: 2,3V 100mA (DC)
So I expected 2,3V when I measured the voltage with no load (I mean I measured only the terminal voltage). However, I got 6.9V.
No problem, I said, because I connected less and less resistance into the circuit, and realised that the voltage decreases. It's a good result, because I know that a correct generator works like this: the load is connected in series with the internal resistance of the generator, so the generator is a voltage divider circuit with the load in series.
After this measure, I interpret the characteristic table of the charger like it shows correct values only if you connect it to expected resistance.
Later, just to make it completely sure, I tried the second and third chargers.
Second is: INPUT: 100-240V, 50-60HZ, OUTPUT: 5V 0.7A (DC)
Third is: INPUT: 100-240V, 50-60HZ, OUTPUT: 4.9V 450mA (DC)
I expected very similar results, namely, the terminal voltage must to be much higher than the values presented on the cover.
However, I got the same results shown on the charger. I tried it over and over again with different value resistances but didn't succeed to measure lower voltage (the lowest value resistance was 200ohm).
So, because of these results, I have got the following questions:
1, First is why? If it is true that all voltage source has an internal resistance and I connect in series some resistance, I make a voltage divider circuit. So I should measure different voltages with different resistances.
2, Is it possible that the reason is in the different technology used by the chargers? Because the first has lot more weight than the second and the third (maybe because it uses coils inside)?
3, If it is true that the characteristic table shows correct values only if you connect it to specified resistance, you should get a different voltage if you wire it with higher or lower resistance. Or if im wrong, what does a table like this exactly mean? How can I interpret a table like this?
If anyone has good explanation or answer which might help, please don't hold back!
I have probem with measuring some voltage sources which were chargers of various electronic equipments (for example beard trimmer, mobile phones).
I have exactly 3 chargers and have problem with 2. Each have an own characteristic table which clearly says how much voltage can you use with and how much voltage does it produce (with the current value as well).
Let me call the three charger first, second and third.
The first charger made me surprise. It's table says:
PRI: 220-240V 50-60Hz, SEC: 2,3V 100mA (DC)
So I expected 2,3V when I measured the voltage with no load (I mean I measured only the terminal voltage). However, I got 6.9V.
No problem, I said, because I connected less and less resistance into the circuit, and realised that the voltage decreases. It's a good result, because I know that a correct generator works like this: the load is connected in series with the internal resistance of the generator, so the generator is a voltage divider circuit with the load in series.
After this measure, I interpret the characteristic table of the charger like it shows correct values only if you connect it to expected resistance.
Later, just to make it completely sure, I tried the second and third chargers.
Second is: INPUT: 100-240V, 50-60HZ, OUTPUT: 5V 0.7A (DC)
Third is: INPUT: 100-240V, 50-60HZ, OUTPUT: 4.9V 450mA (DC)
I expected very similar results, namely, the terminal voltage must to be much higher than the values presented on the cover.
However, I got the same results shown on the charger. I tried it over and over again with different value resistances but didn't succeed to measure lower voltage (the lowest value resistance was 200ohm).
So, because of these results, I have got the following questions:
1, First is why? If it is true that all voltage source has an internal resistance and I connect in series some resistance, I make a voltage divider circuit. So I should measure different voltages with different resistances.
2, Is it possible that the reason is in the different technology used by the chargers? Because the first has lot more weight than the second and the third (maybe because it uses coils inside)?
3, If it is true that the characteristic table shows correct values only if you connect it to specified resistance, you should get a different voltage if you wire it with higher or lower resistance. Or if im wrong, what does a table like this exactly mean? How can I interpret a table like this?
If anyone has good explanation or answer which might help, please don't hold back!
