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| + | ====== GCA94 8 Input power efficient current detector, also suitable for high current G and 1 Track. ====== | ||
| + | [[english|{{ rocrail-logo-35.png}}]] | ||
| + | [[:english|Content]] -> [[:hardware-en|Hardware]] -> [[:hardware-en#interfaces|GCA]] | ||
| + | * [[mgv-overview-en|The GCA modules]] | ||
| + | \\ | ||
| + | |||
| + | ^^^^By Richard Andrews, Helmut Schäfer and Peter Giling ^^^^ | ||
| + | \\ | ||
| + | |||
| + | ===== Description ===== | ||
| + | The current detector [[http://wiki.rocrail.net/doku.php?id=mgv93-en|GCA93]] is a reliable way to creatie feed-back in your layout.\\ | ||
| + | But many railroaders experience the 1,2 Volt loss of power as not appreciable.\\ | ||
| + | And also, the current is limited to the maximum load of the bridge rectifiers on the input side of GCA93.\\ | ||
| + | That will basicly disable the use of GCA93 with G-track or 1-track railroaders.\\ | ||
| + | So we created a better solution.\\ | ||
| + | Richard Andrews had this same thought and has been experimenting with different options by using a current tranformer more or less directly connected to A/D converter.\\ | ||
| + | In that way, without any form of amplification, it is hard to reach the minimal 2,6 Volt, you need to activate an input suitable to be used straight to digital systems.\\ | ||
| + | It was fearly easy to add an amplificator to it, but that also increased the sensitivity to distorsions.\\ | ||
| + | In Germany, Helmut Schäfer created a different approach, using two transistors of which the first one is in normal conducting state.\\ | ||
| + | This eliminates the sensitivity to distorsion, as always produced by running trains.\\ | ||
| + | [[http://www.digitalzentrale.de]] sells this board in two or four ports.\\ | ||
| + | This superb design of Helmut Schäfer is permitted to be used for the GCA94.\\ | ||
| + | GCA94 is made to accept 8 inputs, and can be used like GCA93, straight to GCA50, CAN-GC2 or GCA_PI02\\ | ||
| + | No measureable power loss is the result, and there is no need to protect each input with a PTC Fuse, like on GCA93.\\ | ||
| + | The unit is functional compatible with GCA93, also each input has its own indicator led.\\ | ||
| + | One of the two wires to the rails is feeded through any of the coils, which will mostly be sufficient for any locomotive or illuminated waggons\\ | ||
| + | For more sensitivity, a second or third loop through the coil is possible, which could be necessary when you like to detect also\\ | ||
| + | 10K resistors, mounted between the two wheels of a waggon.\\ | ||
| + | One other way to increase the sensitifity is to feed both rail wires through the coil, **but in opposite directions**.\\ | ||
| + | |||
| + | ===== The board, professionally made. ===== | ||
| + | | {{:gca:gca94_pict03.png?700}} | | ||
| + | | though parts are reasonably small, \\ it is still a rather simpel unit for do it yourself. \\ In the GCA-kits these resistors are all 125 mW small metal film types. | | ||
| + | |||
| + | ===== The hardware ===== | ||
| + | | {{:gca:gca94_sch.pdf|The schematics}} | | ||
| + | | {{:gca:gca94_pcb.pdf|Printed circuit with parts positions}} | | ||
| + | | {{:gca:gca94_partslist.pdf|The list of parts}} | | ||
| + | \\ | ||
gca94-en.txt · Last modified: 2018/11/12 08:56 (external edit)
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