16 Hours Adjustable Timer Circuit Diagram


The 16 hours adjustable timer is an electronic device that is used to control the time period for any specific task or function. This timer can be set for different intervals as per the requirement of the user. It is an important device used for several purposes, including home appliances, gardening, and other industrial applications. This diy circuit is one of the electronic projects for beginners/

The timer was designed for switching off a battery charger after a predetermined time to avoid overcharging. It may, however, be used for a number of other applications as this is a simple electronic project. It may be switched off before the predetermined time has elapsed and may later be re-triggered by a simple push-button switch, S1. No need any special components for this circuit. In the quiescent state, current drain is negligible. The two ICs are used in this circuit i.e. 4060 and 4093 with BC327-25 transistor.

Circuit Diagram

of 16 Hours Adjustable Timer

This amplifier can be designed using a few basic components. The circuit diagram of this project is shown below.

16 Hours Adjustable Timer Circuit Diagram
16 Hours Adjustable Timer Circuit Diagram

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Components List of 16 Hours Adjustable Timer

Following is the list diy circuit components for this simple electronic project :

4060 IC x 1
4093 IC x 1
BC327-25 PNP Transistor x 1
2.2uF Capacitor x 1
1uF Capacitor x 1
150nF Capacitor x 1
100k Resister x 2
470k Resister x 2
47k Resister x 1
3.3k Resister x 1

Working Explanation of 16 Hours Adjustable Timer

The timer is switched on by briefly pressing switch S1. If the switch is then not touched again, the timer remains on for a period determined by time constant R4-C2. If during this period the switch is pressed again briefly, the period is started anew. But if, however, the switch is pressed for a time exceeding time constant R-C during the predetermined period, the equipment being controlled is switched off. This time constant may be adapted to individual requirements by altering the value of R1 or C1.


The timing period (R4-C2) may be changed by altering the value of R4 and/or C2. It must be borne in mind. however, that the value of R4 must remain greater than that of R5 and R6.

The slightly unorthodox configuration of the oscillator in IC ensures that the polarity of capacitor C2
does not change, so that an electrolytic type may be used here. With component values as specified, the ‘on’ time is six seconds per nanofarad of the value of C2. This means that when, for example, the value of this capacitor is 10 uF, the ‘on’ time is more than 16 hours.

When the supply voltage is 9 V, the base current of output transistor T is around 2.5 mA, which, for a voltage drop of only 0.1 V, results in an output current of up to 100 mA. If this is insufficient for a particular application, a different type of transistor may be used, or the BC327-25 fol- lowed by a relay or a MOSFET stage. If the output current is not required to be as large as stated, the value of base resistor R3 may be increased.

The supply voltage should be not less than 4 V, since the oscillator stops operating below 3.5 V. At a supply voltage of about 5 V, the base current of T1, and thus the output current, is rather smaller than stated. However, lowering the value of R3 is not advisable, since the output of gate IC2a is high- impedance.

Conclusion of 16 Hours Adjustable Timer

In conclusion, the 16 hours adjustable timer is an important device that can be used for a wide range of applications. With its adjustable time modification, it is a versatile and flexible tool that offers convenience and control over your tasks. Regardless of your specific requirements, the 16 hours adjustable timer can provide a reliable solution to fulfill your needs.

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16 Hours Adjustable Timer Circuit Diagram
16 Hours Adjustable Timer Circuit Diagram
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