A Crystal Clock with 1 Transistor - the Pierce Oscillator

RE: A Crystal Clock with 1 Transistor - the Pierce Oscillator

Jan Cumps — Tue, 23 Feb 2021 19:30:00 GMT

I won a shopping cart with this project. Here are some of the goodies I ordered.

LF411CDLF411CD precision high-speed JFET-input Operational Amplifier

Snap SocketSnap Socket, Anti-Static, Push & Clinch

[View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-404657dd-7089-478b-b5fb-1ddfe3ba3975/5658.contentimage_5F00_207171.png:620:465]

Ferrite CoreFerrite Core

Enamelled Copper wireEnamelled Copper wire, 18 AWG

[View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-404657dd-7089-478b-b5fb-1ddfe3ba3975/4760.contentimage_5F00_207172.png:620:465]

JumpersJumpers for DIN mount connection blocks

FerrulesFerrules

[View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-404657dd-7089-478b-b5fb-1ddfe3ba3975/2548.contentimage_5F00_207173.png:620:465]

There were a few items in backorder: BF256BBF256B JFET and an Earth bonding plugEarth bonding plug.

RE: A Crystal Clock with 1 Transistor - the Pierce Oscillator

kmikemoo — Wed, 03 Feb 2021 04:12:04 GMT

[mention:acaf6a9338de4eef8f6717d5561ed01d:e9ed411860ed4f2ba0265705b8793d05] I finally made time tonight to breadboard this circuit. 2N5457 JFET, 10uH inductor, 10nF capacitor, 7.023 MHz crystal. 7.018 MHz output. 2.8VDC in. 2v p-p out. OLD coin cell batteries so they drained down quick.

VERY COOL circuit. Thanks for sharing.

RE: A Crystal Clock with 1 Transistor - the Pierce Oscillator

mudz — Tue, 26 Jan 2021 19:08:48 GMT

Wohoo, that's a lot of work for a sweet little one-transistor crystal oscillator.. [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-404657dd-7089-478b-b5fb-1ddfe3ba3975/contentimage_5F00_938.png:16:16]

Interesting Project, nice work [mention:acaf6a9338de4eef8f6717d5561ed01d:e9ed411860ed4f2ba0265705b8793d05] !

RE: A Crystal Clock with 1 Transistor - the Pierce Oscillator

dubbie — Thu, 26 Nov 2020 15:49:27 GMT

Jan,

You have a throw away box - that you haven't thrown away! I find that bits just disappear by themselves. I suspect they might be falling off the edge of my desk but I don't want to look.- just in case I find everything I've lost actually is on the floor at the back of my desk. It would be a lot of things.

Dubbie

RE: A Crystal Clock with 1 Transistor - the Pierce Oscillator

jc2048 — Wed, 25 Nov 2020 12:22:48 GMT

Nice simple circuit and an interesting one to experiment with.

I tried it in a simulator and got this. This is for an imaginary 10.27MHz crystal. It's all very notional: the gm of the FET will be different to yours; it's a simplified electrical model of the xtal; I've put in some small Cs for parasitics on your board; and I guessed a value for the RFC resistance. But it does oscillate, which is nice, even if it's way more enthusiastic about it than the one you've built. Note: I injected a little of the series-resonance frequency to get it started, so the start-up curve probably won't match what you see in real life either.

[View:/resized-image/__size/620x312/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-404657dd-7089-478b-b5fb-1ddfe3ba3975/4520.contentimage_5F00_193244.jpg:620:312]

[View:/resized-image/__size/620x312/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-404657dd-7089-478b-b5fb-1ddfe3ba3975/3124.contentimage_5F00_193245.jpg:620:312]

Think I might have answered the wrong homework question there.

Here's a homework question for you: Are you comfortable putting a waveform that's swinging around the supply rail voltage like this into the clock input of an IC?

RE: A Crystal Clock with 1 Transistor - the Pierce Oscillator

jw0752 — Wed, 25 Nov 2020 03:08:58 GMT

Hi Jan,

I checked my inventory and I had a 2N5459 which is an N Channel JFET so I was able to build the original circuit. It is amazing what a nice simple circuit it is. Here is my bread board with a 16 MHz crystal

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and here is the Oscilloscope reading of the output:

[View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-404657dd-7089-478b-b5fb-1ddfe3ba3975/5280.contentimage_5F00_193243.jpg:620:465]

I will now try a few different crystals and do a little more study on the circuit. Thanks for the posting and the project tonight.

John

RE: A Crystal Clock with 1 Transistor - the Pierce Oscillator

jw0752 — Tue, 24 Nov 2020 20:08:41 GMT

Hi Jan,

Thanks for the post. I will have to play with this tonight.

John

RE: A Crystal Clock with 1 Transistor - the Pierce Oscillator

genebren — Tue, 24 Nov 2020 19:42:33 GMT

Nice oscillator. This was a nice clear dive into a very nice little circuit. Well done!