Would appreciate help

[Rick Spalding]

I need to set up a remote light for notification of ushers in my church. I would like to use a bright LED (Red) at the remote location. I have a relayed transformer using a 24 volt circuit from the remote point to the activation switch downstairs from the sound booth. The transformer has 120v input ....a relay to a switch that will turn on and off the power 120 v using 24 v . Two wires -in (120v) two wires to the switch (24v)and two wires out 120 v.

I would like to use a step down transformer (Can be cheap adapter) to supply 5v to an LED at the remote station ...and also have an LED light at the switch when activated. I have a six conductor (Cat 5) cable run between the points.

If I have the transformer at the remote location what would the circuit look like to accomplish my goal. The switch is at 24 volts ....If possible I would like to have 5 volts flowing to and from the remote switch to stay in code using the cat 5.

I know I am making this more complicated than necessary so I guess the question is will anyone give me a schematic to do this.

 

[MikeMl]

Why not just use the 24Vac to Light the LED directly? Put a Silicon rectifier diode backwards across the LED to protect it from reverse voltage; put a current limiting resistor in series with the LED/diode combination. The resistor value/Wattage depends on the allowed forward current through the LED (most likely 30mA or so).

 

[crutschow]

Why not just use the 24Vac to Light the LED directly? Put a Silicon rectifier diode backwards across the LED to protect it from reverse voltage; put a current limiting resistor in series with the LED/diode combination. The resistor value/Wattage depends on the allowed forward current through the LED (most likely 30mA or so).

To minimize the 30Hz flicker that a half-wave rectifier generates, you could use a bridge rectifier to power the LED. The LED will also tend to be brighter for a given average current. Put the current-limiting resistor in series with either the LED or the bridge.

 

[Rick Spalding]

need help

I have to use 5 volts at 20-50 ma to stay in code since I ran cat5 in the ceiling and not in conduit.

Shouldn't I be able to use a low cost 5 volt dc adapter (forget the transformer) at the switch....use a dpdt switch and wire it with an LED at the switch using a 1000 ohm resister on in series on the positive out pole for the local led and another in series to the remote led (another resister in that line..how do i use the rectifier....positive to negative ....negative to positive bridge between the led legs? could someone draw a schematic and insert it here....it would help this incompetent old man.....thanks I really feel foolish asking such a stupid question.

 

[Diver300]

If you are using a 5 V adaptor, a 1000 ohm resistor (known as 1k) will probably make the LED a bit dim, but that's fine if you can see it OK. If the 5 V adaptor is DC, you don't need a rectifier.

You probably only want an SPST switch, if you want both of the LEDs to light at the same time. You can use a DPDT switch as a SPST switch, but only connect to two terminals of it. I've seen several instances of people making things far more complicated than they need by having switches or relays with lots of terminals and somehow thinking that they have to use all the terminals.

 

[MikeMl]

Here is how I would do it. 9V is safe, and is allowed as a signaling voltage on CAT 5. Both LEDs light when the button is pushed. A 9V Alkaline battery will outlast your present pastor. Using a battery is two orders safer than using a plug-in Wall-Wart.

I sized the resistor on the assumption that the forward voltage drop of your LEDs is ~2V, and that they are bright enough with 20mA flowing through them while the switch is closed. If your LEDs are much different than that, write back, and I will adjust the resistor...

For starters, try a resistor anywhere from 220 to 270 Ohms