Hmm... what should i do with the reset leg? Vcc right? I don't think i need it
and t=R1C1 right?

thanks and good night

 

Hello,

So you want to detect a 1kHz tone to turn on a led.
Take a look at the LM567.
More info can be found in the links of this page:
http://www.educypedia.be/electronics/pll.htm

Greetings,
Bertus

 

man... i gave the monostable (trigger leg2) the 1khz freq. if i transmit the 1khz or if not - it gives the same output voltage at 3 leg.
i think that the monostable is working beacuse i tried connecting manually leg 2 to gnd and the output voltage was changed.

 

bert.. thanks for your answer... it cant be done with converting freq. to voltage?
I don't have this chip and it's a little problem for me to get it.

 

Guys thanks for your help
I built a lowpass - highpass filters and it semms to work.. i have some problems with my highpass i hope it will be fine

 

hi,
I'm looking for the simplest way of converting the output of an optical microsensor to a voltage. The sensor is used to determine the rotation speed of a small shaft by means of a disc with small slits... it's basically a square-wave output with a 'low' of 600mV and a 'high' of 1.8V... as the shaft rotates faster, the frequency simply increases...

so what i need is basically a way to convert this change in frequency to a change in voltage...

if anyone can point me in the right direction i'd appreciate it greatly

thanks!

Hi, I am looking to the same circuit as I need to convert frequency to voltage , a 12V pulse input to 12-24 V range output according to the frequency .
what is your solution to your question, did you make the circuit? share please .

 

Hi, I am looking to the same circuit as I need to convert frequency to voltage , a 12V pulse input to 12-24 V range output according to the frequency .
what is your solution to your question, did you make the circuit? share please .

Frequency-to-voltage and voltage-to-frequency chips exist if that is what you are looking for. If you are looking for a signal that indicates for a particular frequency, then an LM567 tone decoder will likely be the best option.