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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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11th May 2022, 8:40 pm | #41 |
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Re: Mr.French's Dynamic Mutual Conductance Tester.
34mA in the triode-connected list, 48mA in the pentode-connected list for the EL84, with appropriately different Vg1 bias values.... Enough to give a noticeable difference in Gm just from that, so the ratio of Ia to Ig2 is easily lost.
David
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12th May 2022, 9:52 am | #42 | |
Dekatron
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Re: Mr.French's Dynamic Mutual Conductance Tester.
Quote:
Lawrence. |
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12th May 2022, 11:40 am | #43 |
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Re: Mr.French's Dynamic Mutual Conductance Tester.
True, there is not a lot of difference. But we're going round the same circle again.
Strapping G2 to A to put a pentode or a tetrode into 'triode mode' for the purpose of measuring its Gm, as asked in post 33, does introduce a SMALL error in the result. Not strapping it avoids this error, so why not avoid the error and get a more accurate result. Most people, if offered a choice between a 100 gramme and a 105 gramme bar of the same chocolate for the same price in a shop would not choose the disadvantaged deal. Even though the difference is small. Errors are best avoided if they can be. If avoidance has a cost, then a judgement has to be made on whether it's worthwhile, but if it's easy then it's the proverbial no-brainer. Small errors can be insidious, they can be cumulative, and systematic errors tend in this direction, so minimising errors is a good habit. David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |