Difference between revisions of "Colpitts Crystal Oscillator"
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** Hand select close values from a pile of crystals | ** Hand select close values from a pile of crystals | ||
** Useful for [[Crystal Filter Design|design of crystal filters]] | ** Useful for [[Crystal Filter Design|design of crystal filters]] | ||
| − | * Made from | + | * Made from junk box parts |
** (2) 2N3904 transistors | ** (2) 2N3904 transistors | ||
** Standard value 1/4W resistors | ** Standard value 1/4W resistors | ||
| − | * Design from [https://www.amazon.com/Experimental-Methods-Design-ARRL-Inc/dp/087259923X Experimental Methods in RF Design] | + | * Design from [https://www.amazon.com/Experimental-Methods-Design-ARRL-Inc/dp/087259923X Experimental Methods in RF Design] - Fig 7.69 |
** Built by others (W2AEW, IMSAIGuy, etc) | ** Built by others (W2AEW, IMSAIGuy, etc) | ||
| − | * Runs from | + | * Runs from 4V to >16V |
| − | ** May | + | ** May run at higher voltages, didn't tempt fate |
* 15mA with 4.44 MHz crystal at 12V | * 15mA with 4.44 MHz crystal at 12V | ||
Revision as of 20:21, 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
- 4.44 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
