Why doesn't function loop, loop on input? - python-3.7

Question

I want to use the function serial_circuit with three different inputs (1,2,3). The function is suppose to accept multiple inputs from user until
user hits return, end program and sums up all inputs. The program only takes one input and display it.
def serial_circuit(num1):
num = 0
while(True):
try:
num += num1
except:
break
return num
print("1.Solve for serial resistance: ")
print("2.Solve for serial coils: ")
print("3.Solve for parallel capacitors: ")
choice = input("Enter choice: ")
if choice == '1':
num1 = float(input("Enter resistor value: "))
num = serial_circuit(num1)
print(f"Total resistance = {(num)} ohms")
elif choice == '2':
num1 = float(input("Enter coil value: "))
num = serial_circuit(num1)
print(f"Total inductance = {(num)} henrys")
elif choice == '3':
num1 = float(input("Enter capacitor value: "))
num = serial_circuit(num1)
print(f"Total capacitance = {(num):.6f} farads")

Answer 1

One of your problems is that you have the return statement inside the loop - notice your indentation - during the first iteration of the loop the last thing that will happen within the loop is returning from the serial_circuit function.
Another problem is that you are asking for the input only once - outside of the loop.
Take a look at this solution:
def serial_circuit(text):
num = 0
finishedEntering = False
while(not finishedEntering):
try:
received_input = input(text)
if received_input == "":
finishedEntering = True
else:
num1 = float(received_input)
num += num1
except:
break
return num
print("1.Solve for serial resistance: ")
print("2.Solve for serial coils: ")
print("3.Solve for parallel capacitors: ")
choice = input("Enter choice: ")
if choice == '1':
num = serial_circuit("Enter resistor value or hit enter to finish: ")
print(f"Total resistance = {(num)} ohms")
elif choice == '2':
num = serial_circuit("Enter coil value or hit enter to finish: ")
print(f"Total inductance = {(num)} henrys")
elif choice == '3':
num = serial_circuit("Enter capacitor value or hit enter to finish: ")
print(f"Total capacitance = {(num):.6f} farads")