Hello all,
I am new here and have a specific issue that I'd like to clear up. I run an N scale model railway and would like to use relays to switch sections of track on and off through a digital decoder. I expect to use this decoder: Digitrax.com: TF4 Quad DCC Function Decoder which has 4x 125mA (250mA peak) outputs.
My power supply will be via the track power, which is 13.8V DC 20A: https://www.electro-tech-online.com/custompdfs/2010/10/ps2012.pdf.
I am wanting to minimise the current going to the relays, so I was going to go with a 5V relay with the following characteristics:
Max pick up voltage: 3.75V DC
Min drop out voltage: 0.25V DC
Coil resistance: 69 Ohm
Nominal operating power: 0.36W
That's the plan. Here's the problem:
I don't know what resistors to use to minimise the current going to the relay so that I don't burn out the decoder. Can anyone explain how to calculate that?
Cheers
Nige'
I am new here and have a specific issue that I'd like to clear up. I run an N scale model railway and would like to use relays to switch sections of track on and off through a digital decoder. I expect to use this decoder: Digitrax.com: TF4 Quad DCC Function Decoder which has 4x 125mA (250mA peak) outputs.
My power supply will be via the track power, which is 13.8V DC 20A: https://www.electro-tech-online.com/custompdfs/2010/10/ps2012.pdf.
I am wanting to minimise the current going to the relays, so I was going to go with a 5V relay with the following characteristics:
Max pick up voltage: 3.75V DC
Min drop out voltage: 0.25V DC
Coil resistance: 69 Ohm
Nominal operating power: 0.36W
That's the plan. Here's the problem:
I don't know what resistors to use to minimise the current going to the relay so that I don't burn out the decoder. Can anyone explain how to calculate that?
Cheers
Nige'