Difference between revisions of "Colpitts Crystal Oscillator"
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* Lots of extra noise | * Lots of extra noise | ||
** In plastic box | ** In plastic box | ||
| + | ** 3rd harmonic down about 20 dB | ||
[[file:XTAL-Osc-FFT-01.PNG]] | [[file:XTAL-Osc-FFT-01.PNG]] | ||
Revision as of 19:37, 20 August 2021
Features
- Colpitts Crystal Oscillator
- Junkbox parts
- (2) 2N3904 transistors
- Standard value 1/4W resistors
- Useful for binning crystals
- Hand select close values from a pile of crystals
- Useful for design of crystal filters
- Design from Experimental Methods in RF Design
- Built by others (W2AEW, IMSAIGuy, etc)
- Runs from 7V to 16V (may go higher, didn't tempt fate
- 15mA with 4.44 MHz crystal at 12V
Prototype
- Cut square PCB material for raised pads
- Build on single side Copper clad PCB material
- Large ground plane
Prototype Scope Caps
- UUT = 4.4433 MHz crystal
- Rigol DS1054Z - 59 MHz scope (100 MHz mod)
- UltraScope
- 8 Digits Frequency Counter shows 4.432298 MHz
- Waveform triangular
- Lots of extra noise
- In plastic box
- 3rd harmonic down about 20 dB
W2AEW Video
- Wes Haywood EMIRFD cirvuit
PCB
