temperature sensor with digital output

[circuity]

Hi,
this is my circuit. I have several questions:
a) i dont have any output at the VOUT (2) of LM35DT. Why?
b) how can i replace the LED display with 7-segment display. What do i need to add?
c) transformer with what current rating should i use?
d) what brigde rectifier should i use?. Please tell the model number.

Thanx

View attachment 38521

 

[audioguru2]

a) i dont have any output at the VOUT (2) of LM35DT. Why?

It needs an amplifier to boost its output of only 10mV/degree C.

b) how can i replace the LED display with 7-segment display. What do i need to add?

Program the microcontroller for it.

c) transformer with what current rating should i use?

The circuit's current is very low. Calculate or measure it.
The LM317 regulator is missing a resistor, therefore its output voltage is only 1.25V.

d) what brigde rectifier should i use?. Please tell the model number.

The circuit's current is very low. Calculate or measure it.

 

[circuity]

can i use a uA741 to amplify the output of LM35DT..?
what microcontroller should i use...?
im a newbie in electronic circuits...... ???

thanx audioguru for ur fast reply

 

[Tony_Stoynov]

Hi,
Yes you can, but must think about input offset voltage, you must make the input compensation. I can suggest to use more precision OPAMP, something like MCP606/7/8/9 from Microchip or OP-41, OP-07 etc.