Timer circuit II

Rating: 5.00/10 (19Votes cast)

Category: Meter Counter Circuits / Timer Circuits
This circuit is also crossed to: MCU Circuits
Views: 1414
Rank: 0

Timers are fundamental building blocks, and as such timers are found in practically every electronic circuit. There are many kinds of timers, available off-the-shelf from resellers of electrical and electronics goods, because circuits circuits involving timers have thousands of practical applications. In this article we will explain how to build six different timers from the same base circuit. Nutchips are ideally suited for building timers. Not only the timers differ only for the truth table programmed inside the Nutchip, there is also room for ingenuity, and you master the basics you can customize the timer adding your custom logic to the truth tables shown here.The schematic diagram is quite straightforward. SW1 is a pushbutton used for starting the timer. The oputputs are set logic level 0 when the timer is not triggered, and to logic level 1 when the timer triggers. The relay driver transistor TR1, which receives its base current from Nutchip output OUT1 via the resistor R1, supplies enough current to energize the relay. The diode D1, connected in parallel with relay's coil, safeguards the transistor against the high voltage that builds up on the coil when it is energized or released. The relay is a 5V coil type, .and it must be choosen accordingly to the load you want to drive (e.g. AC or DC load). Ask your electrician for a suitable model, and always keep an generous safety margin (usually 50% or more) in excess the maximum specs declared by the manufacturer. For example, it is safer not to surpass 500W for a relay specified for continuous 1000W load maximum by the manufacturer. As an example, for a 12Vac halogen lamp requiring a current of 3 amperes, use a 24Vac/ 6 ampere relay with a coil rated for 5Vdc. The schematic shows a ceramic resonator connected to Nutchip pins 4 and 5. This kind of clock source ensures a timing accuracy usually better than 1%, which is suitable for most uses. If you are looking for an even more accurate timer (e.g. for daily or weekly timers), a better choice is the quartz clock oscillator as shown in the base circuit collection. The same page shows alternate reset circuits that can be used when maximum reliability is required (this circuit uses a simplified RESET, the pin connects to the positive rail through an RC network made from R2 and C2). visit page.

The schematic diagram is quite straightforward. SW1 is a pushbutton used for starting the timer. The oputputs are set logic level 0 when the timer is not triggered, and to logic level 1 when the timer triggers. The relay driver transistor TR1, which receives its base current from Nutchip output OUT1 via the resistor R1, supplies enough current to energize the relay. The diode D1, connected in parallel with relay's coil, safeguards the transistor against the high voltage that builds up on the coil when it is energized or released. The relay is a 5V coil type, .and it must be choosen accordingly to the load you want to drive (e.g. AC or DC load). Ask your electrician for a suitable model, and always keep an generous safety margin (usually 50% or more) in excess the maximum specs declared by the manufacturer. For example, it is safer not to surpass 500W for a relay specified for continuous 1000W load maximum by the manufacturer. As an example, for a 12Vac halogen lamp requiring a current of 3 amperes, use a 24Vac/ 6 ampere relay with a coil rated for 5Vdc. The schematic shows a ceramic resonator connected to Nutchip pins 4 and 5. This kind of clock source ensures a timing accuracy usually better than 1%, which is suitable for most uses. If you are looking for an even more accurate timer (e.g. for daily or weekly timers), a better choice is the quartz clock oscillator as shown in the base circuit collection. The same page shows alternate reset circuits that can be used when maximum reliability is required (this circuit uses a simplified RESET, the pin connects to the positive rail through an RC network made from R2 and C2). http://www.nutchip.com/progetti/timer_en.htm

Related circuits

Timing circuit

Load current starts approximately 0 RC

Self Retriggering Timed Generator Circuit

When power is first applied to the circuit, 02 begins to charge via LED1, R3, and R4. When the voltage across C2 reaches Ul`s input trigger level, the output of Ul at pin 6 goes positive for a period that is determined by the values of and it! r That turns Ql on, discharging 02 through D1 and...

0.1 To 90 second timer

The timer interval starts when power is applied to circuit and terminates when voltage is applied to load. 2N2646 is used in oscillator which pulses base 2 of D5K

Sequential timing

By utilizing both halves of the dual timer it is possible to obtain sequential timing. By connecting the output of the first half to the input of the second half via a 01 Âµ-F coupling capacitor, sequential timing may be obtained. Delay ti is determined by the first half and h by the second...

Long-time-timer

When used as a stand-alone device, ZN1034E from Ferranti can provide timed intervals ranging from 1 second to 19 days, although the rc time constant is only 220 seconds. The ZN1034E includes an internal voltage regulator, an oscillator, and a 12-stage binary counter. The total delay time...

Timer 1 Minute To 400 Hrs Circuit

This ultra wide range timer uses a 555 timer base, two 4017Bs and a 4020B that act as frequency dividers that can be switched in and out.

Sequential timer

Many applications, such as computers, require signals for initializing conditions during start-up. Other applications such as test equipment require activation of test signals in sequence. SE555/NE555 circuits may be connected to provide such sequential control

Tele Timer Circuit

The circuit is built around a 555 oscillator/ timer. The circuit provides two time periods. The long-running time period is adjustable from about 1 to 10 minutes, and the short time period is preset to about three seconds. Here`s how the dual timer operates. When the power is switched on, G2...

Electronics - 555 Timer, A Microchip Project