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Quartz Watch Tester

We can check any mechanical watch by hear tick – tick sound whether it is working or not but to check any electronics quartz watch which does not have second needle is quite tedious work because no sound is produce. To check this type of watch a circuit “Quartz Watch Tester” is used.

Circuit Description

The circuit of quartz watch tester utilize a amplifier IC a coil of few turn and a transistor. The pulse produced by watch is pick–up by coil of 30 – 50 turns made from 42 SWG copper wire over 45mm * 4 mm iron nail. The pulse from coli is given to base of transistor T1 through capacitor C9. Transistor T1 is used as pre – amplifier. The output of pre – amplifier i.e. from collector of transistor T1 is given to input pin 8 of IC1 through capacitor C7. IC1 (TBA810) is a audio amplifier IC which further amplify the pulse up to desired level and fed to loudspeaker through capacitor C6 for output.

circuit diagram of quartz watch tester copy

PARTS LIST

Resistors (all ¼-watt, ± 5% Carbon)

R1, R2 = 100 Ω

R3 = 100 KΩ

R4 = 2.2 KΩ

R5 = 390 KΩ

R6 = 470 KΩ

Capacitors

C1 = 220 µF/10V

C2 = 0.001 µF

C3 = 0.005 µF

C4, C5, C7 = 100 µF/16V

C6, C10 = 1000 µF/16V

C8 = 33 µF/16V

C9 = 1 µF/50V

Semiconductors

IC1 = TBA810 (audio amplifier)

T1 = BC147

Miscellaneous

SW1 = ON/Off switch

LS1 = 8 Ω loudspeaker

L1 = 30 – 50 turns of 42 swg copper wire over 45mm*4mm iron nail

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