Difference between revisions of "Colpitts Crystal Oscillator"
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* 4.433 MHz crystal - worked | * 4.433 MHz crystal - worked | ||
| + | * 16 MHz crystal - worked | ||
* 27 MHz crystal - didn't work | * 27 MHz crystal - didn't work | ||
Revision as of 21:05, 20 August 2021
Contents
Features
- Colpitts Crystal Oscillator
- Useful for binning crystals
- Hand select close values from a pile of crystals
- Useful for design of crystal filters
- Made from junk box parts
- (2) 2N3904 transistors
- Standard value 1/4W resistors
- Design from Experimental Methods in RF Design - Fig 7.69
- Built by others (W2AEW, IMSAIGuy, etc)
- Runs from 4V to >16V
- May run at higher voltages, didn't tempt fate
- 15mA with 4.44 MHz crystal at 12V
Tested With
- 4.433 MHz crystal - worked
- 16 MHz crystal - worked
- 27 MHz crystal - didn't work
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
- FFT
- 0-50 MHz
- Shows lots of extra noise
- In plastic box
- Fundamental - zoomed in
- FFT 3rd harmonic
- 3rd harmonic down about 20 dB
W2AEW Video
- Wes Haywood EMIRFD cirvuit
PCB
