Hi I am a railway modeller looking for some help I work with 12v dc
I have a 12 v pcb which has a signal output to drive a open collector input which I don’t really understand
what I want to do is drive a timer relay with this pcb is it possible ?
An "open collector" output is just a transistor without any already-connected load; in effect, it works like a switch to the 0V connection (or power -).
The timer input would have to be compatible with 12V, and you connect that input between the open collector output and +12V.
You can connect the open collector output to a relay coil, then use a NO contact of the relay ( +V to com, NO to timer) to trigger your timer.
or
you can use a transistor to invert the output signal to drive the timer input.
But...we really need to see the block occupancy detector output circuit and Timer info to be sure.
Can you post part numbers?
I think it should be wired this way (see below).
The Block detector output signal is normally held high(12v) via R1. When the DCC input becomes active, the Block Detector output signal will change to low(0v) and trigger the Timer Module. However, this assumes the Block Detector output is normally OFF (high).
If the Block Detector output is normally ON (low), then the wire to the Timer needs to be moved to the HL_TRIG input, so that when the output turns OFF (high), it will trigger the timer.
Whether the Block Detector output is normally ON or OFF depends on the DCC commands.
The block detector is current driven (it is wired in series with the DCC feed to the rack), so it only activates the LED in the opto when there is something (like a locomotive) drawing current in that section of the track.
Following schematic is almost the same as the board pictured above.
There is a +/-15vdc bipolar signal being received at the input (the power pack signal).
So is the bridge doing nothing?
I think the resistor is 330 ohm.
The block detector is current driven (it is wired in series with the DCC feed to the rack), so it only activates the LED in the opto when there is something (like a locomotive) drawing current in that section of the track.
Following schematic is almost the same as the board pictured above. View attachment 134054