# Calculating I4 in Combination Circuit

#### ericgibbs

Joined Jan 29, 2010
17,126
hi,
OK,
So using Ohms law I=V/R, what is the current thru R4.?
E

#### aeln269

Joined Oct 18, 2020
31
so I = V/R V is 1, R is 15 1/15 is 0.06666667 round to 2 significant numbers is 0.067

#### ericgibbs

Joined Jan 29, 2010
17,126
hi,
OK,
I would advise you when asked for a 2decimal place answer, is to do the calculations to 3 deci places and round up the final answer to two places.
The actual current is 76mA , but you have 66.7' due to limiting your answers to 2 deci places .OK.
E
Do the sums again to 3 deci places.

#### aeln269

Joined Oct 18, 2020
31
are you referring to all of the calculations? or just the I=V/R? Because Its just 1/15 so I cant specify anymore...

Also thank you for your help. I think I had the process right.

#### ericgibbs

Joined Jan 29, 2010
17,126
hi,
Consider the 24V/105R = 0.228A

So Vdrop 100R is V= 100R*0.228A =22.8V

24V- 22.8V = ~1.2V across R4

Now that you have stepped thru the circuit in a visual way, you should now be able to build up an equation.

E