Why It Might Seem to Work (Sometimes)
3. Understanding the Nuances of Relay Activation
Sometimes, against all odds, a 24V relay might appear to function, albeit weakly, with a 12V supply. This usually happens because relays have a "dropout voltage" and a "pull-in voltage." The pull-in voltage is the minimum voltage required to initially activate the relay, while the dropout voltage is the voltage at which the relay deactivates.
If your 12V supply is particularly robust or if the relay is exceptionally sensitive (perhaps due to manufacturing variations), the 12V might exceed the pull-in voltage under certain conditions. However, this is far from guaranteed, and even if it does work initially, the relay's performance will likely be unreliable and unpredictable in the long run.
Furthermore, external factors like temperature can affect the relay's internal resistance, influencing the current draw and, consequently, its activation. A colder environment might make it harder to activate, while a warmer environment might make it slightly easier. These unpredictable variables contribute to the unreliability of using an incorrect voltage.
Think of it like trying to start a car with a weak battery. It might crank a few times and even sputter to life occasionally, but you wouldn't rely on it to get you across town. Similarly, relying on a 24V relay operating with 12V is asking for trouble.
