httpimgurcompVtjPBu Attached is a photo of an DC what is DC

http://imgur.com/pVtjPBu

Attached is a photo of an DC (what is DC?) circuit. The circuit is a series and parallel combination of resistors and one voltage source. There is one node where the current splits (branches off) into resistor R3 and R4. I have shown a new symbol called \"ground\" which is where the voltage is zero. Then there is a \"rise\" in voltage from ground (0 V) TO 12 Volts due to the potential energy of the battery. Calculate the total current from the battery. How do you do that? You only need to know two concepts: Ohms Law and the equivalent resistance of the R3 and R4 combination.

Solution

From the circuit R3 in parallel with R4 ,The equivalent Resistance is Req=R3*R4/(R3+R4)=10*10/(10+10)=5 ohms

so Req=5 ohms

Now R1 and R2 and Req are in series so current I=Vbat/(R1+R2+Req)=12/(10+10+5)=12/25=0.48 A

Voltage across R4 = volatge across R3 = Volatge across Req(R3 parallel R4) =I * Req (ohms law)

all volatge equal because they are in parallel

So Voltage across R4=I*Req=0.48*5=2.4 V

Current through R4= Volatge across R4( V)/R4 ohms law

so I=V/R4=2.4/100=0.024 A