|
A thermostat
is a device for regulating the temperature of a system so that the system's
temperature is maintained near a desired set point temperature. The thermostat
does this by controlling the flow of heat energy into or out of the system. That
is, the thermostat switches heating or cooling devices on or off as needed to
maintain the correct temperature.
A thermostat may be a control unit for a heating or cooling system or a
component part of a heater or air conditioner. Thermostats can be constructed in
many ways and may use a variety of sensors to measure the temperature. The
output of the sensor then controls the heating or cooling apparatus.
Many thing
in our daily need that can be easily by implement a simple applied technology.
So our life become easy and comfort. We can make anything work automatic, or
work without our intervention so if we forget to run it, or to turn off it, they
will be done by their shelf.
By a simple
applied technology, such as electronics, we can solve many simple problem as
mentioned above. With the small dimension of electronic component and small
power too, we can realize our need, such as automatic lamp, remote controller,
water tank level controller.
Beside all
that mention above, we can make many device that valuable to our need, such as
decorative lamp, amplifier, detector etc. The simple applied electronic circuits
are divided in to two groups, analog and digital circuitry.
Analog
electronic circuits are those in which signals may vary continuously with time
to correspond to the information being represented. Electronic equipment like
voltage amplifiers, power amplifiers, tuning circuits, radios, and televisions
are largely analog (with the exception of their control sections, which may be
digital, especially in modern units).
In digital
electronic circuits, electric signals take on discrete values, which are not
dependent upon time, to represent logical and numeric values. These values
represent the information that is being processed. The transistor is one of the
primary components used in discrete circuits, and combinations of these can be
used to create logic gates. These logic gates may then be used in combination to
create a desired output from an input. In this page you can find one of the
circuit.
Thermostat Elektronik
NTC adalah jenis resistor yang akan mengecil nilai
resistansinya ketika terjadi kenaikan suhu lingkungannya. dengan demikian
NTC dapat digunakan sebagai sensor untuk mengendalikan nyala heater (pemanas).
Rangkaian untuk mengendalikan heater adalah seperti terlihat pada Gambar 1.
Pada rangkaian Gambar 1, NTC digunakan bersama resistor sebagai rangkaian
pembagi tegangan. Ketika suhu di sekitar NTC naik, maka tegangan pada
masukan inverting (-) akan ikut naik. Jika kenaikan tegangan pada masukan
inverting melampaui masukan non-inverting (+), maka output op-amp akan
rendah, sehingga relay akan mati sehingga saklar terputus yang akan
mematikan heater. Untuk mengatur batas suhu yang kita inginkan, maka nilai
R2 dapat ditala pada harga tertentu. Rangkaian ini disebut juga sebagai
rangkaian on-off controller, yang dapat digunakan untuk mengatur suhu, namun
histeresisnya cukup besar.

Gambar 1. Rangkaian Thermostat Elektronis.

|