10mhz timebase osc

dendad

Joined Feb 20, 2016
3,890
The output level may not be enough to trigger the 74LS14. It needs to swing above and below the required thresholds. That could be the problem.
 
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dendad

Joined Feb 20, 2016
3,890
I think the signal needs to swing between about 0.8V to 1.8V for the 74LS14 to operate. So, a full 5V swing is not needed.
 

dendad

Joined Feb 20, 2016
3,890
You could try to have a resistor divider on the input of the 74LA14 to set it to about 1.5V, and then connect the oscillator signal to it via a 10nF capacitor.
Try a 2K2 from input to 0V, and an 8K2 from the input to +5V.
This may (or may not) work.
 

michael8

Joined Jan 11, 2015
156

Thread Starter

radioshack5209

Joined Nov 25, 2020
68

Kevil

Joined Jun 28, 2020
37
Don't mess with all that active and passive components. Use MEMS oscillator which gives you reliable perfect rectangle signal with just one IC.

LSE MEMS Oscillator 32.768 kHz, IM890-IDCC-32.768 ILSI:

 
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andrewmm

Joined Feb 25, 2011
1,640
I must first say,
WELL DONE YOU,
its amazing how few people now days know what an oscillator circuit is , till they make one by mistake when they thought the were making an amplifier.

Second

The reason most people don't make or understand oscillators, is as @Kevil says,
off the shelf much better oscillators are pennies,
just have hunt on ebay for good enough, or your distributor such as digikey for good parts at a few pennies more.
 

Ian0

Joined Aug 7, 2020
2,699
The output level may not be enough to trigger the 74LS14. It needs to swing above and below the required thresholds. That could be the problem.
You could always amplify it with a 74HCU04 with a 10M resistor across it, but you didn't have any 74HC; because if you did, you could have made the ever-so-reliable Pierce oscillator.
 
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