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Build Your 9-Second LED Timer & Relay Circuit 9V
Description
This schematic demonstrates a visual nine-second postponement utilizing ten light-emitting diodes before activating a twelve-volt relay. Upon actuation of the reset switch, the 4017 decade counter will be returned to its initial zero state, causing the LED driven from pin 3 to illuminate. The output from the 555 timer at pin 3 will maintain a high state and the voltage across pins 6 and 2 of the timer will be approximately three volts. When the switch is deactivated, the transistor operating in parallel with the timing capacitor (22uF) is disabled, permitting the capacitor to begin charging and the 555 timer circuit to generate a roughly one-second timing pulse to the decade counter. The counter increments with each rising edge at pin 14, and this operation is enabled by pin 13 being at a low voltage level. Once the ninth count is achieved, pins 11 and 13 will be active, halting the counter and powering the relay. Increased delay durations can be achieved by using a larger capacitor or a greater resistor across pins 2 and 6 of the 555 timer.
4017 Decade Counter
The 4017 is a versatile integrated circuit frequently utilized as a decade counter. This IC counts from 0 to 9, utilizing its ten outputs for each count. Its primary function is to provide a sequential numbering system, making it ideal for applications such as digital clocks, frequency dividers, and simple counting circuits. Pin 14 provides the clock input, while pin 13 enables the counting process. Outputs from pins 0-9 represent the count values. It’s a common and readily available component suitable for educational and prototyping projects.
Circuit diagram
