Fun And Games With Spice

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Mike H
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#1 Fun And Games With Spice

Post by Mike H »

Not as in the deoderant for men that is :D


Wot a larf...


#1. Parallel fed Hartley oscillator, capacitor tapped
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#2

Post by Mike H »

#2. Parallel fed Hartley oscillator, inductor tapped
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#3

Post by Mike H »

#3. Series fed Hartley oscillator
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#4

Post by Mike H »

#4. Reaction coil oscillator.

Spice was having a bit of a headache with the first two cos it keeps trying to put a huge current through the tuning cap(s)

The latter two are much more accurate frequency wise re actual tuned circuit values.
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#5

Post by Mike H »

Before you ask, negative bias is applied to the grid by charging the grid series cap through the forward conduction of grid to cathode on the positive half cycles, grid ends up at a mean average negative DC. This stabilises the output Voltage at some constant level. In all cases I was getting about 100V peak across R3.
 
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Nick
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#6

Post by Nick »

Adding parasitic capacitance and resistance to coils helps spice to make sense of the world.
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#7

Post by Mike H »

I dare say!

Might figure that out later

What I found particularly interesting is the triode current, in all cases it's just a series of short pulses. I.e. it's the tuned circuit that makes the sinusoidal waveform, the valve just gives it a 'quick boot' once per cycle to keep it going.

Also the reaction coil type seems the most efficient, maybe that's why they tend to be seen most often in ack-tew-al circuit diagrams.


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#8

Post by pre65 »

What the **** is a " Parallel fed Hartley oscillator, capacitor tapped " :?:

Aha ! maybe I'm getting an idea ? Is it used in jam making, to mix the fruit up. :wink: :lol: :lol:
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Mike H
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#9

Post by Mike H »

It was thought up by some bloke called Hartley I imagine. Got it out of a book. Can't say if it's the same fellah who invented jam.

I used to like the "elegance" of it but now I'm beginning to understand why I used to have the odd problem with them!


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#10

Post by pre65 »

Mike H wrote:It was thought up by some bloke called Hartley I imagine. Got it out of a book.

I used to like the "elegance" of it but now I'm beginning to understand why I used to have the odd problem with them!

.
You're just being clever for the sake of it now ! :lol: :lol:
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#11

Post by Mike H »

Can you tell I can't think of anything better to do? :lol:


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#12

Post by Nick »

What I found particularly interesting is the triode current, in all cases it's just a series of short pulses. I.e. it's the tuned circuit that makes the sinusoidal waveform, the valve just gives it a 'quick boot' once per cycle to keep it going.
Hence the "freewheel" description. Its in just this sort of use where the idea of class C start to make sense.
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#13

Post by Mike H »

Educational, have to say that for it :D


I was wrong No. #1 is a Colpitts not a Hartley. :oops:



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#14

Post by Mike H »

Improved version of the reaction coil version.
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#15

Post by Mike H »

Improved version of the Colpitts
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