Information collated from Massoth Technical, Service, Support, and independent additional research of all relevant documentation.
From the range of Massoth decoders, they may have a mixture of reinforced (Amplified, NEG) and unreinforced (Logic, POS) Function Outputs.
Particular attention should be paid to identifying the correct type of Function Output for connection of a consumer (load).
A reinforced (Amplified) output is connected between +22V and the switching (Function) output.
When the switching output is OFF, +22V will be at the output, and as there is now no potential difference, no current flows.
When the switching output is turned ON, GND will be present at the output, now the consumer (load) has the full or as defined by any CV's for dimming, voltage available.
An unreinforced (Logic) output is connected between the switching output and GND.
When the switching output is OFF, GND will be at the output, and as there is now no potential difference, no current flows.
When the switching output is turned ON, +5V will be present at the output, now the consumer (load) has the full or as defined by any CV's for dimming, voltage available.
As these unreinforced (Logic) outputs, A5 to A8 are limited to 10mA, they are not suitable for direct connection to a consumer (load).
To convert these unreinforced to reinforced outputs, a resistor and a suitable transistor are required, and a connection to the Decoder + and the Decoder GND.
Note, that the transistor selected may have a hFE gain factor of many times the 10mA unreinforced (Logic) output, attention is drawn to the Technical Specification of each decoder that will have an unreinforced output converted to a reinforced output, not to exceed the total Amp rating for all decoder outputs.
The two following circuits/designs are as recommended by Massoth.
Transistor, Base from the decoder unreinforced (Logic) output, Emitter to the decoder GND, Collector now the reinforced (Amplified) output, as per a recognised and regular decoder Function Output.
The first, for High Loads on A5 – A8, utilises a BC337 NPN Transistor, base resistor of 1K Ohm, maximum permissible consumer (load) up to 300mA.
The second for connecting a Massoth 8414002 Automatic Uncoupler with the outputs A5 - A8 from a decoder, utilises a BC547 NPN Transistor, with a base resistor of 1K Ohm.
Wiring the Uncoupler directly.
Black: Decoder - (GND),
Brown: FA, Signal Control to an open collector function output, 50mA and greater switching to Decoder - (GND).
Red: Decoder + (up to 200mA).
The third circuit, is a collaborated and researched design using a FDV301N MOS transistor, no base resistor is required.
This is at present being evaluated, and under continuous testing, for use across a diverse range from different decoder Manufacturers.
(G) Gate (Base) from the decoder unreinforced (logic) output. (Resistor not required)
(S) Source (Emitter) decoder GND.
(D) Drain (Collector) now the reinforced (Amplified) output, as per a recognised and regular decoder Function Output.
