Battery tester

This assembly is a battery tester quickly without the use of a diet, it can test the batteries of 1.5 V to 15 V.
The switch S1 determines the two voltage ranges that can test the circuit. A position can test the battery 3V to 15 V while the other position can be tested only 1.5V

List of components:
Resistors
R1 1/4W 2K2
R2 3R3 1/4W
R3 10R 1/4W
R4 4K7 1/4W
R5 33K 1/4W
R6, R7 100K 1/4W
R8 220K 1/4W
R9 330K 1/4W
R10 500K 1/4W

Polyester capacitors:
C1, C2 10nF 63V
C3-C7 100nF 63V

Electrolytic capacitor:
C8 220μF 35V

LED red 5mm LEDs:
D1, D7

Diodes:
D2-D6 1N4148 75V 150mA

FET:
Q1 2N3819

Transistors:
Q2, Q3 BC337 45V 800mA NPN

Integrated Circuits:
IC1, or IC2 7555 TS555CN Cmos Timer

Push button:
P1

Switch:
SW1

Battery test:
PURPOSE