Rosemary Ainslie circuit demonstration on Saturday March 12th 2011

[neptune]

I am somewhat disappointed that there is no one on here that is able to answer my questions about the 555 timer circuit that I asked in my last post . I do expect Rosemary to answer as it is not her field of expertise . These questions are at the very heart of this device .

[FatBird]

Neptune, Please repeat your question about the 555 & I will try to answer it for you.


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[nul-points]

I am somewhat disappointed that there is no one on here that is able to answer my questions about the 555 timer circuit that I asked in my last post . I do expect Rosemary to answer as it is not her field of expertise . These questions are at the very heart of this device .

1) - usually several volts (depends on actual device used);
     were there any side-effects on the drive-level due to multi MOSFETs being used in parallel?

2), 3) i think we're waiting to see some close detail waveform data from Rosemary to confirm this - or is this now available to us somewhere?

4) need to establish first if the oscillation sustains with true disconnection of SigGen - and with what remnant DC bias connection (eg. resistive/capacitive connection to ground) - again, need close view of one or two driving pulses

5) other possible causes of negative voltage on the gate could be, say, voltage spikes caused by inductive or capacitive coupling to high-voltage or current pulses nearby

hope this helps
np

http://docsfreelunch.blogspot.com/

[neptune]

@FatBird , thanks . My questions are
1 The output of the 555 timer circuit is a square wave ,what is the voltage difference between these 2 states .
2 Is it true  that the 2 states are a positive voltage and zero volts , or is it a positive voltage and a negative voltage .
3 What positive voltage is necessary on the gate of the Mosfet to turn it completely on .  is it about 7.5 volts ?
4 If the output of the 555 toggles between pos volts and zero , can you see any way in which the Mosfet gate can become Negative?
Rosemary talks about the desired oscillation occurring when the gate is negative , and this has happened for up to 2 or 3 seconds .If this is the case , one could at that point disconnect the 555 from the gate and replace it with a small battery giving a negative potential , and the oscillation might continue indefinitely .What do you think ?

[neptune]

@Nul-points . You replied whilst I was typing . Thanks for replying , your info is very helpful