Circuit Wiring Solution: temperature

Showing posts with label temperature. Show all posts

Sunday, October 5, 2014

Simple Temperature Relay Circuit

This is a design circuit for temperature relay that can be used to signal a fire or set point for temperature monitoring function. You need to adjust P1 so that T1′s base voltage is 0.5V smaller than the emitter voltage at a temperature a little bit lower than the desired triggering (switching) temperature. This is the figure of the schematic circuit;

If the temperature increases then T1 and T2 start conducting and the relay is closed (ON). If you want to use it as a cold relay or to signal an inferior temperature limit, then Th1 and P1 change places. After the relay is triggering you need to open switch S1 in order to stop the circuit. The nominal value of P1 must be chosen according to the used NTC thermistor and the switching temperature to be adjusted.

Wednesday, September 17, 2014

IC LM35 Temperature Sensor Characteristics

LM 35 temperature sensor IC is a IC chip production Natioanal Semiconductor which serves to determine the temperature of an object or space in the form of electric scale, or can also be defined as an electronic component that is used to change the temperature changes are accepted in the electrical wholesale changes. LM35 temperature sensor IC temperature change can change a change in voltage at the output. LM35 temperature sensor IC requires +5 volts DC source voltage and DC current consumption of 60 mA in operation. Physical form LM 35 temperature sensor is an IC chip with packaging that varies, in general packaging LM35 temperature sensor is packaged TO-92 as shown in the figure below.

IC LM35 Temperature Sensor Characteristics

From the picture above it can be seen that the temperature sensor IC LM35 basically have 3 pin that serves as a source of supply voltage of +5 volts DC, as a result of sensing the output pin in the form of a change in the DC voltage and Vout pin to Ground.

IC LM35 temperature sensor characteristics are:

Temperature sensitivity, with linear scaling factor between voltage and temperature 10 mVolt / º C, so it can be calibrated directly in centigrade.
Have the accuracy or the accuracy of the calibration is 0.5 º C at 25 º C.
Has a maximum operating temperature range between -55 º C to +150 º C. Working at a voltage of 4 to 30 volts.
Has current low at less than 60 mA.
Have a low self-heating (low-heating) of less than 0.1 º C in still air.
Has a low output impedance is 0.1 W for 1 mA load.
have Nonlinearities only about ± ¼ º C.

Thursday, August 21, 2014

Temperature Candle Using LED

LED based projects require a lot of skill and hence only experienced schema designers try out these diagram. But there are also a few diagram in this genre that can be done by amateur electronic hobbyists. The temperature candle is one such schema. Read on to know more about this.

The hardware components that are required to build this schema are listed below:

Microcontroller
Temperature Sensor
RGB LED
PCB

The schema design is pretty simple. The LED is made to flicker by the microcontroller and the color is based on the ambient temperature at that point. The temperature of the room can be known by observing the color of the LED.

The temperature value is obtained in degree Celsius. This value is received as a result of pressing the reset button on the PCB. This value can also be obtained by providing power to the device. Once the device is powered up, the change in temperature is indicated. The blue LED is triggered for a temperature increase of 10 degrees. The red LED is triggered for a temperature increase of a single degree.
Suppose, the ambient temperature is 23 degrees celsius, The schema works in such a way that the blue LED is made to blink twice and the red LED is made to blink 3 times. Soon after this, an orange colored flicker is observed as the LED goes into canfle mode.

Since through hole components are used in this schema, it is very cheap to construct and the components can be easily soldered. The schema also contains a jack for connecting to a Microchip Pickit 3 programmer / debugger. This reduces the complexity involved in code modification and download.