# How to create "DC offset voltage" in crystal oscillator ?

#### Ngô Đình Nhân

Joined Jan 8, 2017
45
Hi all

I am doing a Pierce Oscillator with a quartz crystal. But I don't know how I can create a DC offset at point (a) or (b) in that circuit ?

Please see me attached image for more clear.

So, does any give me some recommendation ? I really appreciate your helps.

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#### Picbuster

Joined Dec 2, 2013
990
add an opamp or transistor plus a negative supply

Picbuster

#### Ngô Đình Nhân

Joined Jan 8, 2017
45
Hello Picbuster

thanks for feedbacks

Do you think your solution will affect to resonance frequency of circuit ?

Best regards
Ngo, Dinh Nhan

#### Bordodynov

Joined May 20, 2015
2,468
Usually (when using a CMOS inverter) between the points a and b put a resistor. At frequencies of 32 kHz, this is 10 - 30 Mega ohms. And frequencies greater than 1 megahertz are approximately 100kΩ -1MgaOhm.

#### Ngô Đình Nhân

Joined Jan 8, 2017
45
Usually (when using a CMOS inverter) between the points a and b put a resistor. At frequencies of 32 kHz, this is 10 - 30 Mega ohms. And frequencies greater than 1 megahertz are approximately 100kΩ -1MgaOhm.
Hello Bordodynov

In a real circuit, I had areadt put a 2.2Meg Resistor between a and b.

But my problem is that i need a DC offset at a or b as my draw in image.

So, do you have any recommendations?

#### Bordodynov

Joined May 20, 2015
2,468
What kind of inverter are you using? Detailed information increases the opportunity to help you. But I can say that the resistor stabilizes the DC operating point. At the input, a DC offset is supported equal to the inverter switching threshold.

#### Danko

Joined Nov 22, 2017
849
I am doing a Pierce Oscillator with a quartz crystal. But I don't know how I can create a DC offset at point (a) or (b) in that circuit ?
Use this circuit:

#### Bordodynov

Joined May 20, 2015
2,468
See

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#### Ngô Đình Nhân

Joined Jan 8, 2017
45
Thank you so much, all

I am going to test this circuit topology.

Best regards, all

#### Danko

Joined Nov 22, 2017
849

#### fernandopv

Joined Oct 20, 2018
10
Hi all

I am doing a Pierce Oscillator with a quartz crystal. But I don't know how I can create a DC offset at point (a) or (b) in that circuit ?

Please see me attached image for more clear.

So, does any give me some recommendation ? I really appreciate your helps.
Perhaps you need to add this: (it will work with senoids too after some cycles)