Relays: Difference between revisions
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= Activate a relay using 3.3V operating voltage microcontrollers = | = Activate a relay using 3.3V operating voltage microcontrollers = | ||
The circuit below uses an electromechanical (E/M) relay to switch between 5V and 9V operating voltages. It is unlikely you are going to need to switch between 5V and 9V in your designs, but the choice here, indicates the [https://en.wikipedia.org/wiki/Switch#Contact_terminology SPDT] functionality of a common E/M relay. | |||
We use a common 5V voltage regulator ([https://en.wikipedia.org/wiki/78xx 7805]) to drop the 9V of the battery to 5V, as required to operate the relay. The 2N2222 NPN transistor is <!-- doing the low-side switching to --> activating the relay using an Arduino Nano, with operating voltage 3.3V. | |||
[[File:3v-to-5v-or-9v-arduino-volt-reg-NPN bb.jpg|thumb|alt=5V relay activation using Arduino Nano (3.3V)|5V relay activation using Arduino Nano (3.3V)]] | [[File:3v-to-5v-or-9v-arduino-volt-reg-NPN bb.jpg|thumb|alt=5V relay activation using Arduino Nano (3.3V)|5V relay activation using Arduino Nano (3.3V)]] | ||
Latest revision as of 01:45, 2 March 2026
Relays come into different types. We are mostly using electromechanical and reed relays in the Studio.
Links and components
- 5V reed relay SIL05-1A72-71D
- Datasheet: https://docs.rs-online.com/82fc/0900766b8003309b.pdf
- RS online: https://se.rs-online.com/web/p/tungelementrelaer/3492884P
Activate a relay using 3.3V operating voltage microcontrollers
The circuit below uses an electromechanical (E/M) relay to switch between 5V and 9V operating voltages. It is unlikely you are going to need to switch between 5V and 9V in your designs, but the choice here, indicates the SPDT functionality of a common E/M relay.
We use a common 5V voltage regulator (7805) to drop the 9V of the battery to 5V, as required to operate the relay. The 2N2222 NPN transistor is activating the relay using an Arduino Nano, with operating voltage 3.3V.
