diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Digital Source (http://www.diyaudio.com/forums/digital-source/)
-   -   not gate oscilator (http://www.diyaudio.com/forums/digital-source/21911-not-gate-oscilator.html)

sss 24th October 2003 01:23 PM

not gate oscilator
 
hello
i want to make a square wave oscilator using one or two NOT gates , i know theres a way to do it but i forgot how:)

SY 24th October 2003 01:34 PM

You only need one inverter. Run a resistor from output to input. Connect a capacitor from input to ground. Voila! An oscillator!

peranders 24th October 2003 01:57 PM

Note that the inverter must have a schmittrigger input!

CMOS40106

If you have two inverters

1 connect those in series.

2 Resistor between input #1 and output #2

3 Cap between input #1 and output #1.

CMOS 4011 or 4001

Very simple and more predictable than the 40106 type because of the uncertain logic levels in the 40106. Philips has much less hysteresis than other brands. It's also temperature sensistive.

I recommend a 4001 or 4011 oscillator. Resistor values between 500 ohms to 10 MOhms! 10-100 kohms is normal I think. Cap values fom 47-100 pF, no upper limit.

sss 24th October 2003 06:04 PM

Quote:

Originally posted by SY
You only need one inverter. Run a resistor from output to input. Connect a capacitor from input to ground. Voila! An oscillator!
how to calculate freq?
and what is the duty cycle , do i need schmittrigger input for that circuit?

SY 24th October 2003 06:11 PM

Figures you would ask me that, now that I'm 30 km from my notebook ;)

Frequency was something like 4 times 1/RC. I'm sure someone will correct me... Duty cycle was not exactly 50%, but the parts count is low.

sss 24th October 2003 06:19 PM

thanx SV
i'll calculate it myself then
hhhhm duty cycle is a problem , i'll need schmittrigger input gate to get 50% right ?

peranders 24th October 2003 08:03 PM

Quote:

Originally posted by sss


how to calculate freq?
and what is the duty cycle , do i need schmittrigger input for that circuit?

The duty cucle of a 4001 or 4011 oscillator is very near 50% but if you want exactly 50% you can add a D-flip-flop.

f = 0.23/(R*C) I think, not sure. It's not 1/(2*pi*R*C) but not far from it.

You can use gates with schmittrigger but you don't have to.

Hint: Check the datasheet for CMOS4541 which has an oscillator I'm talking about. BTW: You can in fact use this IC!


All times are GMT. The time now is 10:22 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2