| W@ldur |
I built a comparator using TL074, actually 1/4 of that.
everything works!
when I send audiosignal into comparator, LED will flach according to the signal.
but it flashes too fast. I want it to flash not so much-I want it to work for 30seconds after it has light once.
signal comes for 1/2 seconds, led works for 30secs.
can i do it adding a hysteresis to comparator or I have to add some transistor ana capacitor as well?
Thanx..
W@ldur |
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| peranders |
| You can build a peak detector. |
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| W@ldur |
no need for a peak detektor, I only want short flash into a longer "burning".
time relay or smtg. |
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| jackinnj |
hysteresis reduces a comparator's susceptibility to noise, eliminating false triggering.
what you really want to do is add a time constant to one of the inputs of the comparator -- V = E^-(t/RC) -- then you have to figure a way of discharging the capacitor as the input impedance is not low enough to drain it.
take a look at Rod Elliot's VU meter project and you'll get the general idea. |
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| davidsrsb |
| You need a monostable to stretch the pulses to seconds. |
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| W@ldur |
problem solved.
between input and comparator a diode. from comp. input a 47uF lyt. to GND and parallel with it a 100k potensiometer.
really, it works.
it is called signal intergrating or smtnh like that. |
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