LC_Meter

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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 ???
 

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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.
 
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 ?
 
How i can except Lx/Cx component when i do the calibration
Click to expand...
Just don't connect any external cap (Cx) or inductor (Lx).
i know i can except c2 using relay ?
Click to expand...
As I understand the circuit, C2 stays connected always and is allowed for by calibration. You don't 'except' it.
 
alec_t said:
Just don't connect any external cap (Cx) or inductor (Lx).
.
Click to expand...
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 ?
 
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 ?
Click to expand...
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 .
 
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 ?
 
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.
 
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"
 
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
 
Can't you just add an offset in your code to zero the meter?
 
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.
 
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
 
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