Difference between revisions of "Colpitts Crystal Oscillator"
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== Features == | == Features == | ||
| − | * Colpitts Crystal Oscillator | + | * Colpitts Crystal Oscillator useful for [[Crystal Filter Design|design of crystal filters]] |
* Useful for binning crystals | * Useful for binning crystals | ||
** Hand select close values from a pile of crystals | ** Hand select close values from a pile of crystals | ||
| − | |||
* Made from junk box parts | * Made from junk box parts | ||
** (2) 2N3904 transistors | ** (2) 2N3904 transistors | ||
Revision as of 16:35, 19 September 2021
Contents
Features
- Colpitts Crystal Oscillator useful for design of crystal filters
- Useful for binning crystals
- Hand select close values from a pile of crystals
- 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
- 18 mA at 14V
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
Scope Caps
- UUT = 4.4433 MHz crystal
- 8 Digits Frequency Counter shows 4.432285 MHz
- Rigol DS1054Z - 50 MHz scope (100 MHz mod)
- UltraScope
- Waveform triangular
Prototype
SMT Build
]
tinySA Measurements of SMT Build
- SMT build
- 12V power
- 4.43 MHz crystal
- Measured +8.6dBm into 50 ohm load
- 40 dBm attenuator to protect tinySA
- 8 Digits Frequency Counter shows 4.432298 MHz
- 4 to 30 MHz scan
- Rich even and odd harmonic content
- -60 dBm down outside of harmonics
- 4 to 100 MHz
- 5V Operation
- +4.3 dBm
W2AEW Video
- Wes Haywood EMiRFD circuit
PCB - Rev 2 -3D
