| Electronics > Beginners |
| HOW to add ameter RIGHT? |
| (1/2) > >> |
| 001:
Hi! I have homebuilt power supply Simple basic 7812 regulator Now I want to add cheap ebay ammeter BUT! If I put meter in series with the load (simply after regulator) some voltage will drop across inner ameter resistance isnt it? But I need for clear 12.00V output at all curents! How to add ameter RIGHT? |
| gigabyte091:
This is the right way to install the ammeter, your shunt will drop like 50 mV or maybe 75 mV at full output current, and i highly doubt this will affect your circuit in any way... You can put ammeter before regulator, but then it will measure output current plus some quiescent current draw from regulator (about 6 to 8 mA for 7812) |
| 001:
75mV is a BIG difference in some mc cases The question is how to eliminate output voltage drop |
| rstofer:
Accept the quiescent current error and put the meter shunt ahead of the regulator. You can account for the error. You could use a Hall Effect current sensor, the internal drop will be a lot less. The resistance is in the single digits of mV - like 1.2 mV for one I just looked at. |
| Momchilo:
If you really want (almost) no voltage drop at all, I would suggest a Hall Effect current sensor. Something like this: https://www.mouser.de/datasheet/2/397/S22PXXXS05-31126.pdf But normally you would use a shunt to measure a power supply output current. |
| Navigation |
| Message Index |
| Next page |