# How to create circuit for low voltage trigger of a relay

I have the relay in the picture above and have it powered with 5 volts. My question is how do I wire up the trigger. Correct me if I'm wrong but I'm assuming that if I send 5v 2a to the trigger pin it will fry it. so how do I drop the multage and or amperage to safely operate this relay. No information came with the relay for the voltage/amperage requirements.

• Please clarify what you want to wire the trigger to. If you want to use a button, you wire it like is shown in the picture. If you want to wire it to, say, a microcontroller, you'll probably want to use a MOSFET. – Selvek Mar 8 '18 at 19:46

My question is how do I wire up the trigger.

You have provided a diagram that shows you. Connect the 'T' input to GND (DC-) once for each change of state.

Correct me if I'm wrong but I'm assuming that if I send 5 V, 2 A, to the trigger pin it will fry it.

1. You don't send 5 V to it. You connect it to ground.
2. Circuits only draw the power they need. If you plug a 20 W lamp into your domestic supply it will draw the current it needs not what the supply is capable of.

... so how do I drop the multage

'Multage' is not an engineering term I am familiar with.

and or amperage to safely operate this relay.

You don't. It will look after itself.

No information came with the relay for the voltage/amperage requirements.

We recommend: "No datasheet? No sale."

The current required by the module will be 99% determined by the resistance of the relay coil. If you have a multimeter and can find the coil pins you can then measure the coil resistance, R. The current, I, can then be worked out from $I = \frac {V}{R}$.

If, for example, the coil resistance is 200 Ω then the current required will be $I = \frac {5}{200} = 0.025 \ A = 25 \ mA$.