40106 oscillator help

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Michael Circuit

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Hello all, I am working on building an oscillator using a 40106. So far I have only been able to get one oscillator out of the 40106. I should be able to get several from a single IC.

DC connected to pin 14
Ground to pin 7
A 4.7 uf capacitor is connected to pin 1 from ground,
A wire is connecting pin 1 to pin 2
A 100 K resistor is connecting pin 2 to pin 3
and my output is pin 4

After looking at several examples online, I should be able to connect my capacitor to pin 1,
my resistor between pin 1 and 2
and have my output be pin 2
but this has yet to work, I am trying to create a dual oscillator but need the single oscillator to work first before i can move forward,
any suggestions?
 
Works in LTSpice. Try a higher value (>50K, < 5meg) for the resistor. You can make the capacitor smaller, as long as it is >~100pF.
 

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i must be missing something

pin 14 dc in
pin 7 ground
pin one capacitor
pin 1 to pin 2 resistor
pin 2 output

i am connecting the possitive wire of a small speaker to pin two and grounding the negative, i should be able to hear audio correct? i can hear it in the set up posted with my question but i can not hear it when trying these connections.

should i be using a potentiometer for my resistor, i know thats a dumb question, but this still isnt working.
 
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A CMOS inverter cannot drive a speaker; as I told several posts ago, you need an audio power amplifer.

Feed the signal at the inverter output into your home stereo, or your powered computer speakers.

If you use a pot, put a fixed resistor of ~20K in series with it.
 
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IT WORKS! i connected the 40103 to a 741 audio amp and it works, thank you for all of your help everyone. im sure i will have many more questions, i am very new at this
 
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A 741 opamp also cannot drive a speaker properly. As you were told twice, you need a power amplifier. An LM386 is a low power amplifier that drives a speaker to less than half a watt.
 
A 741 is an old opamp that cannot drive a speaker.
An LM386 is a good little power amp that drives a speaker very well if the simple circuit is made like shown in its datasheet.
But many LM386 amp projects on the internet have missing parts that make them perform poorly.
 
I have a question regarding the 40106, As as Single Oscillator It works fine. But as a dual oscillator I can not seem to get each oscillator to perform independently of one another, the rate of the oscillation adjusts both oscillators simultaneously regardless of which potentiometer I adjust. is there any way to correct this problem?
 
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hi,
Do you have separate pots and timing caps for each oscillator also have you decoupled on the +V/0v power lines.?

Are the unused input pins of the 40106 floating.?
 

What is the power supply? If you are using a battery, the effective series resistance of the battery will cause the two oscillators to oscillate in lock-step, especially if you are trying to make them oscillate at frequencies that differ by less than a few percent.

Likely, to make this work, you should use two different hex-inverter chips, bypass capacitors from Vdd to Vss at each chip, and a very well-regulated power supply.
 
ericgibbs said:
hi,
Do you have separate pots and timing caps for each oscillator also have you decoupled on the +V/0v power lines.?

Are the unused input pins of the 40106 floating.?
Click to expand...

Yes I have separate pots and timing caps for each oscillator and the pins are floating. The powers supply is decoupled on the +V/0v power lines. I am using a DC Power Supply instead of a battery.
 
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Michael Circuit said:
Yes I have separate pots and timing caps for each oscillator and the pins are floating. The powers supply is decoupled on the +V/0v power lines. I am using a DC Power Supply instead of a battery.
Click to expand...

hi,
Its important on CMOS devices to connect the unused INPUTs to +V or 0V , I usually connect to 0V

Do you have a diagram to post.?
 
I was thinking about buying some 40106s just for the purpose of having the possibility of 6 oscillators out of 1 chip.
Is this not to be?
Any other chip suggestions for this purpose?
Thank you.
 
YaranAyr said:
I was thinking about buying some 40106s just for the purpose of having the possibility of 6 oscillators out of 1 chip.
Is this not to be?
Any other chip suggestions for this purpose?
Thank you.
Click to expand...

Its possible to use all 6 gates in a 40106 as independent oscillators, good decoupling is essential.
 
ericgibbs said:
Its possible to use all 6 gates in a 40106 as independent oscillators, good decoupling is essential.
Click to expand...

It may not be; I think there is sufficient coupling just due to the impedance of the power supply traces inside the IC package and layout that they will oscillate in lock-step. You will have to try it in an actual circuit. Even on a plug-board, the capacitance from pin-to-pin will be too high.
 

Hi,
If he uses a plug in project board he could have problems due to the high-ish inter connector capacitance

I have seen 40106's used in mini musical organ projects being used as hex oscillators OK.

As you say he will have to try it out, I keep stressing to him the need for very good power rail decoupling.

Have a Good 2011.
 
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