LC_Meter

[Adam2014]

there is a source code (c language) for atmega16 micro_controller to same circuit design ?
Circuit Design :https://www.rfcandy.biz/communication/pic/lcimpsch.gif

 

[Adam2014]

HI
I want the relay RBG 10.2 - 11.05 datasheet

 

[alec_t]

Google for it.

 

[Adam2014]

Hi
I need to know the mode of switch depending on pin 12 state?
is when switch on L mode thus pin12 Low & when switch on C mode thus pin12 High ???

 

[alec_t]

In L mode pin 12 is Low. In C mode pin 12 will be High, provided there is an internal pull-up enabled on pin 12. Without the pull-up the pin will be floating, which is a no-no.

 

[Adam2014]

thanks ... the problem solved
another question How i can except Lx/Cx component when i do the calibration ,, when the calibration depending on L1,c1,C2 only
and then Lx/Cx Taking into account when i do the normal measurements depending on L1,c1,Lx/Cx , i know i can except c2 using relay ?

 

[alec_t]

How i can except Lx/Cx component when i do the calibration

Just don't connect any external cap (Cx) or inductor (Lx).

i know i can except c2 using relay ?

As I understand the circuit, C2 stays connected always and is allowed for by calibration. You don't 'except' it.

 

[Adam2014]

Just don't connect any external cap (Cx) or inductor (Lx).
.

i know that but i ask if the circuit work in the normal measurements and the user ask for recalibration , is he can do this even if there is a connected component ?
Q2) i'm asking for the code , how i can change between L/C mode any time i change the switch position ?

 

[alec_t]

if the circuit work in the normal measurements and the user ask for recalibration , is he can do this even if there is a connected component ?

I wouldn't think so, unless you can program the meter to allow that. The whole point of calibration usually is to 'zero' a meter, to allow for stray inductance and capacitance.
Q2) I don't have it. Ask the circuit designer .

 

[Adam2014]

Hi
i use MCU atmega16 to switch relay (MCU vcc=5volt also relay open with 5volt)
but the problem is the voltage measured from MCU is 3 volt and not enough to switch relay
what the solution ?

 

[alec_t]

Sounds like your relay is drawing more current than the mcu is rated for. You will need a buffer stage between the mcu and the relay.

 

[Adam2014]

i have to use transistor with relay ?

 

[alec_t]

That' my suggestion.

 

[Adam2014]

in general ...
why we prefer relay instead of switch ?
i read thing but need more details "relay keep inductance / capacitance in its minimum range so give more accuracy"

 

[alec_t]

A relay is a switch.

 

[Adam2014]

thanks
there are some problems :
1) when i do calibrating i get capacitance for circuit (c1 + stray capacitance) equal 820pf , but c1= 1nf
thus the capacitance for (c1 + stray capacitance) less than c1 !!!!
2) after calibrating the meter display a value a bout 200pf with out any device under test (DUT) , how i can make that reading 0 pf without any DUT ?
3) when i measure a capacitors in range (10pf - 10nf) i get an accuracy values using my meter
but with values larger than 10nf the reading will be inaccuracy and less than the actual values

 

[alec_t]

Can't you just add an offset in your code to zero the meter?

 

[KeepItSimpleStupid]

That goofy thing has a wierd way of operating a relay. It looks like it uses two ports? What ever happened to the diode to absorb the kickback? I suppose the original designer wanted to assure the relay was off at power up?

To the OP: You have to look at your relay, both the voltage and the current required and to what extent the ports can source and/or sink current. The operate voltage has to be within the limits. I don't like the way the relay is driven.

 

[Adam2014]

thanks a lot
i have a big problem ..
when i measure a capacitors in range (10pf - 10nf) i get an accuracy values using my meter
but with values larger than 10nf the reading will be inaccuracy and less than the actual values

 

[alec_t]

Can't you apply some correction factor in your code?