Re: Crystal tester circuit using a 6C4 and would work with anything, where to find?

As Scott said, any amplifier with gain can be used. Generally, oscillators
do not work over infinite frequency range. If you wanted to check out the
low frequency surplus crystals, you built one with a lot more inductance in
the "plate" lead. Most hf crystals will check out fine in a single
oscillator.

I have built some using an fet for gain and a led to indicate current flow.
Although I have some with meters, generally you are looking for a go / no-go
type of indication. Heath grid dip meter works well, but you need to build
a socket adapter.

I built a single fet gate dip meter using an MPF-102 out of the Handbook. I
used an FT-243 crystal socket for the coil. It works great as a crystal
tester and the meter indicates activity. Great to let me know I have a
dirty crystal. Although it does not work on low frequency crystals, it
works well otherwise.

My favorite is one from Ham Radio. It was a solid state oscillator with an
isolating amp for the counter. It has a built in switched capacitors for
change crystal loads and if you plug in an inductor, it will read out in
inductance. I made adapters for various types of crystal sockets.

It reads overtone crystals quite well.

The big problem is sorting out the drawers full of crystals. The
mathematical odds that you will have and can find just the crystal you need
decreases as the number of crystals increases.

Colin K7FM


.

Relevant Pages

  • Re: Watch Crystal dissipation
    ... tuning fork watch crystals make remarkable ... So the issue is not so much that you want to build any old oscillator and then measure the crystal dissipation. ... If this were me I'd implement the loop shaping in a microcontroller and the multiplier in a multiplying DAC; this would not only allow me to play games with the inherently nonlinear effect of regulating the oscillator output by changing it's damping but it would also let me easily communicate the output level directly, since it would be available internally to the processor. ...
    (sci.electronics.design)
  • Re: Defeating the mantis part 3
    ... different video channels and 2 LCDs hanging in front of your eyes, ... The supply voltage has very little effect on the crystal oscillator frequency. ... pretty hard to cope with higher MHz crystals from a wide variety of ... I was first imagining the output to input path as obvious, ...
    (sci.electronics.design)
  • Re: Digital Crystal Oscillator
    ... working on the project a long way short of having an actual oscillator. ... how to make a crystal oscillate using a digital drive controller? ... The most commonly available 32kHz crystals are teeny and fragile. ... Wescott Design Services ...
    (comp.arch.embedded)
  • Re: Watch Crystal dissipation
    ... tuning fork watch crystals make remarkable ... So the issue is not so much that you want to build any old oscillator and then measure the crystal dissipation. ... If this were me I'd implement the loop shaping in a microcontroller and the multiplier in a multiplying DAC; this would not only allow me to play games with the inherently nonlinear effect of regulating the oscillator output by changing it's damping but it would also let me easily communicate the output level directly, since it would be available internally to the processor. ...
    (sci.electronics.design)
  • Re: Correct crystal oscillator choice.
    ... The project uses a PIC16F84A chip, ... First, what you bought isn't an oscillator, it's a quartz crystal. ... its resonant frequency. ... and since parallel resonant crystals need those ...
    (sci.electronics.basics)