Relay Circuit 9 Second LED TimerThis circuit provides a visual 9 second delay using 10 LEDs before closing a 12 volt relay. When the displace about-face is closed, the 4017 decade adverse will be displace to the 0 calculation which illuminates the LED apprenticed from pin 3. The 555 timer achievement at pin 3 will be aerial and the voltage at pins 6 and 2 of the timer will be a little beneath than the lower activate point, or about 3 volts.
When the about-face is opened, the transistor in alongside with the timing capacitor (22uF) is shut off acceptance the capacitor to activate charging and the 555 timer ambit to aftermath an almost 1 additional alarm arresting to the decade counter. The adverse advances on anniversary absolute activity change at pin 14 and is enabled with pin 13 concluded low. When the 9th calculation is reached, pin 11 and 13 will be high, endlessly the adverse and animating the relay. Longer adjournment times can be acquired with a beyond capacitor or beyond resistor at pins 2 and 6 of the 555 timer.
When the about-face is opened, the transistor in alongside with the timing capacitor (22uF) is shut off acceptance the capacitor to activate charging and the 555 timer ambit to aftermath an almost 1 additional alarm arresting to the decade counter. The adverse advances on anniversary absolute activity change at pin 14 and is enabled with pin 13 concluded low. When the 9th calculation is reached, pin 11 and 13 will be high, endlessly the adverse and animating the relay. Longer adjournment times can be acquired with a beyond capacitor or beyond resistor at pins 2 and 6 of the 555 timer.
