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Live Line Detector Circuit: Build Your 4017 Indicator
Description
When the device is positioned near an energized wire (protected, and even encased within plaster), capacitive interaction between the energized wire and the probe triggers the counter, and consequently, the LED flashes five times per second. This phenomenon arises due to the 4017 integrated circuit dividing the 50Hz mains frequency by ten. Away from a live power source, the device ceases counting, and the LED remains perpetually extinguished.
4017 Decade Counter
The 4017 integrated circuit is a versatile decade counter, commonly utilized in various electronic projects. This IC features ten decade-up/decade-down binary counters, each capable of counting from 0 to 9. It employs an asynchronous, edge-triggered design, meaning it counts only on the rising or falling edge of the input signal. The 4017’s outputs are decoded, providing a convenient way to display the count in decimal format. It's a popular choice for timing circuits, digital displays, and other applications needing sequential counting capabilities. This specific IC operates from a 5V power supply and has several outputs for various counting and decoding functions. The IC's internal circuitry includes Schmitt triggers for noise immunity and a clock oscillator to drive the counting operation. The IC’s package is a 14-pin DIP (Dual In-line Package) that offers easy connection and protection of the pins.
Circuit diagram:
Parts:
- P1 = SPST Pushbutton
- D1 = Red LED (any type)
- C1 = 100nF 63V Polyester or Ceramic Capacitor
- B1 = 3V Battery (two 1.5V AA or AAA cells in series etc.)
- IC1 = 4017 Decade counter with 10 decoded outputs IC
- Sensing probe 3 to 15 cm. long, stiff insulated piece of wire
Notes:
- Sensitivity can be adjusted utilizing a shorter or longer sensing probe.
- Due to the 3V operation, the LED's current limiting resistor is unnecessary.