Grid Frequency Monitor: Tiny Fluctuations Evidenced by LEDs
Materials
Extra info / Update
* Display range 59.8 Hz to 60.2 Hz (60 Hz firmware version)
* Accuracy ±0.0025 Hz
* LED readout with 11 LEDs
* No calibration required
* No SMD components
* Low component count
* Suitable for 230 V and 115 V operation
Gerber file
CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor Green and Gold members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.
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Bill of Materials
R1 = 470Ohm
R2,R3 = 10kOhm
Capacitors
C1 = 100nF MKT, 5mm pitch
C2,C3 = 56pF ceramic, 2.5mm pitch
C4 = 100?F 25V, radial, 2.5mm pitch
C5,C6 = 10?F 16V, radial, 2.5mm pitch
Semiconductors
D1,D2 = 1N4007
IC1 = AT89C2051-24PU (Atmel), programmed, Elektor # 110461-41 (50Hz) or 110461-42 (60Hz)
IC2 = LM2936Z-5.0
LED1, LED11 = LED, red, low-current, 5x2 mm
LED2,LED3,LED4,LED5,LED7,LED8,LED9,LED10 = LED, yellow, low-current, 5x2 mm
LED6 = LED, green, low-current, 5x2 mm
Miscellaneous
K1 = 2-way PCB terminal block, 7.5mm pitch
J1,J2,J3 = 2-pin pinheader, 5mm pitch, with jumper (or wire link), see text
TR1 = AC power transformer, 0.5VA, 2x115V primary, 2x6V secondary, e.g. Block type AVB0,5/2/6)
X1 = 12MHz quartz crystal, HC-49S case
AC adapter case, ABS, approved, to suit local power outlet.

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