Scientific Calculator

Scientific calculatorsare more than just an everyday requirement for any engineer. With features that allow you to assist in solving complicatedtrigonometric exponential, and logarithmic problems in a blink of eyes, scientific calculators are nothing smaller than a compact brain. Let's discover what makes this small sized device function.

Fig. 1: Image of the Scientific Calculator Most of the scientific calculators, irrespective of the manufacturer, come with a tough plastic casing like described above. The layout of the buttons is neat and ergonomic so that calculators can be used for extended time without posing any risk of strain on the wrist. It also guarantees the correct stroke every time, regardless of the size of the finger that is pressing them.

PCB

Fig. 2: Circuit Board along with the LCD Display of a Scientific Calculator A plastic casing houses the PCB, batteries as well as the monitor LCD that is part of the calculator. A double-sided PCB is used to make a scientific calculator. While one side has the COB IC and the necessary circuitry and connections to the LCD The other side includes the keypad. It contains the tracks that generate signals in response to keys that are pressed. The back side of the PCB is shown below.

Fig. 3: Chip on Board Integrated Circuit

Processing Core: COB IC or no COB?

Fig. 4. Integrated Circuit of Scientific Calculator The COB IC can be the most cost effective option as it is a great way to reduce the use of hardware and carries out all the functions of a calculator but usually takes away the ability of it to allow the calculator to be programmable by the user. This also makes the distinction between an ordinary, off the mill pocket calculator designed for multiplication or addition functions or a sophisticated, scientific calculator that can perform a variety of computation. COB ICs are typically used in calculators that are not programmeable. However, those calculators that are programmable do come with a distinct Microprocessor that is packaged or surface mounted based IC that are connected to Flash memory that is external to the. Programmable calculators can be instructed to store user-defined data and formulas. The chip is not clearly visible within scientific calculators too as that will also look like the appearance of a COB IC due because the chips are covered with an epoxy layer. A few acceptable ICs that have been utilized in programmable calculators are the 8502 Microprocessor that has been utilized by HP 35s' series scientific calculators and the ARMv4T chips which are utilized in more robust calculators that offer graph plotting functions and support for inputs to memory externally like memory cards.

Keypad

Fig. 5. Keypad and circuit board from Scientific Calculator Shown in the image above is the reverse aspect of the plastic keypad as well as the PCB. Patterns are drawn onto the PCB surface that generate the signal to the corresponding key , which is then pressed, and transfer to the COB IC. The keypad operates in the same manner as a keyboard does. The switches made of plastic that are visible on the case are linked to a keypad made of rubber. When you press the button, the black rubber mark beneath the keypad's rubber touches the PCB and completes the track to transmit signals.

LCD Display

Fig. 6. LCD Display and the characteristics based on the options offered by the calculator LCD displays in the calculator may be of different sizes and shapes. Although a basic calculator comes with a 16X2 LCD display, the ones enabled by advanced features include an DOT matrix LCD. Higher-end scientific calculators even have a colorful display.Shown in the photo above is a dual line LCD. The top line has a Dot matrix LCD display. While the lower line is an display LCD display with seven segments of numerals. The LCD is connected to the PCB through the aid of a heat seal connector. The term "heat seal" refers to an electronic connector made of polyester film. Two layers of polyester films are joined (sealed) togetherat high temperature, using a conductive paste hence the name heat seal.

Batteries

Fig. 7: Battery Combination of Scientific Calculator The type of batteries used depends on the features of the calculator. More features, or more the display on LCD, the more robust the battery must be. Below is an example of an AA pencil cells combination which provides power to the calculator. Button cell, also known as "AAA" batteries are also employed in numerous calculators. Average life of such a battery pack is around 1-2 years (though it varies with each type of battery and between calculators and calculators). Adding a solar panel enhances the battery life which means that the reason behind replacing the calculator isn't the death of the batteries, but something similar to physical damage caused to dropping it from a certain height. In addition, calculators run on very little power and don't get drained as easily. In order to draw the smallest amount of possible battery power, the calculators are equipped with an Auto Power Off feature. This feature is managed via "Power Control Consumption System" which turns off the calculator in the event that no key is used for a certain time. Typically, this period is between about 7-9 minutes. In the event that the calculator is in the middle of a calculation (which usually does not happen), it saves the information for the convenience of the user.The first calculator that was scientific in nature was launched in the late 1960s by Hewlett Packard and numerous electronic manufacturers followed. Initially expensive and feature restricted the engineers have crammed ever-growing features into the tiny space available since the industry of manufacturing semiconductors continues to grow.