hi
i have a question
if anybody have information please help me
this is possible to add crystal for 555???
or how can increase 555 speed??????

 

What crystal?
Why do you want to add a crystal?
Increase 555 to what speed?

 

This is what the resistor and capacitor do in a 555 circuit. If the 'speed' your talking about is the output frequency.

Here's a 555 circuit calculator that may help you;
http://www.ohmslawcalculator.com/555_astable.php

 

What crystal?
Why do you want to add a crystal?
Increase 555 to what speed?

i use of 555 for convert voltage to frequancyyyy
i want increase speed for convert voltage to frequancy

 

i want increase speed ...

From what to what? Schematic?

 

Use an Lm2917 chip. chip

thanks.but lm2917 convert frequency to voltage not voltage to frequency

 

From what to what? Schematic?

voltage to frequency
with 555
Schematic:

this is work
but i think frequency output have delay
and if possible i want increase speed for convert

 

I have seen crystal oscillators for the 555, but they nail the frequency down. No VCO there. I suspect you seriously do not understand the 555.

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voltage to frequency
with 555
Schematic:

this is work
but i think frequency output have delay
and if possible i want increase speed for convert

This schematic produces an output train of pulses at the same frequency, the only thing changing is the width of the pulses. The input on pin 2 (I assume this is where you want your crystal) retriggers the 555 at a set frequency. The RC network on pins 6 & 7, along with the voltage on pin 5, determine the duty cycle of the output on pin 3. I'm not sure what tw refers to, but I am guessing that it is the time the signal is high.

BTW, I don't know how to decrease the propagation delay inherent to the chips.

 

...but i think frequency output have delay

Any delay is so small that most folks don't worry about it. Changing the control voltage will change the output of the 555 within one clock cycle.

Define your needs. Perhaps you need a PLL.

 

Any delay is so small that most folks don't worry about it. Changing the control voltage will change the output of the 555 within one clock cycle.

Define your needs. Perhaps you need a PLL.

your means is:
if i increase control voltage,
output frequency speed increase?????

 

Any delay is so small that most folks don't worry about it. Changing the control voltage will change the output of the 555 within one clock cycle.

Define your needs. Perhaps you need a PLL.

that was going to b my suggestion.
Obviously its a simple APC-type synth and Ive built maybe a hundred of those in various forms but I dont think I understand exactly what he wants to do either..
King40: maybe you could clearly and simply state what, exactly, you are trying to achieve both in toto (the overall goal of the circ/device), and in particular (w/the delay Q)?

Its entirely possible that there is a significant language barrier functioning here..