This is a simple delay timer circuit designed to control the operation of electrical appliances by providing a delay before they are switched off. The circuit can be set to a fixed time of approximately 5 minutes, although it allows for fine adjustments to the timing. The circuit utilizes the digital IC CD4093, which simplifies the design process. A transistor is employed to drive a relay, enabling control over the power supply to the connected load or electrical appliance. Additionally, an LED indicator (LED1) is included to show when power is supplied to the circuit. The circuit is operated by pressing switch S1 to initiate its functionality.
This delay timer circuit primarily employs the CD4093, a quad 2-input NAND gate with Schmitt trigger characteristics, which ensures clean signal transitions and noise immunity. The timer functionality is achieved through a combination of resistors, capacitors, and the NAND gates, which create a time delay based on the RC (resistor-capacitor) time constant. The timing can be adjusted by varying the resistance or capacitance values, allowing for customization of the delay period.
The transistor acts as a switch, controlling the relay that connects or disconnects the power to the load. When the timer circuit is activated by pressing switch S1, it begins counting down from the set delay time. Upon reaching the end of the countdown, the output from the NAND gate changes state, turning off the transistor and consequently deactivating the relay. This action cuts off power to the connected appliance.
The inclusion of LED1 serves as a visual indicator, illuminating when the circuit is powered. This feature enhances usability by providing immediate feedback to the user. The circuit is designed to be user-friendly, requiring minimal components that are readily available, thus making it an accessible project for both novice and experienced electronics enthusiasts.This be delay timer circuit model to be simple. It be the character delays to close electric all appliances. By fix the time about 5 minute. It can fine decorate the time. When see the circuit uses digital IC number CD4093 make good easy. And use transistor driver relay. It performs to edit the electricity gives with load or the electric appliance s is all. When see our circuit uses electronic part that seek easy. May have no the problem about part. For LED1 use for display when feed power supply reach the circuit. It usability easily just press S1 for begin be usable. 🔗 External reference
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