While designing a 5V relay shield (for Arduino), do I need to short a common pin with coil pins? - Quora
MFJ Auto Electrical - 🔻Ⓢⓘⓜⓟⓛⓔ ⓒⓘⓡⓒⓤⓘⓣ ⓦⓘⓣⓗ 4 ⓟⓘⓝ ⓡⓔⓛⓐⓨ👇 🔹4 pin relays use 2 pins (85 & 86) to control the coil and 2 pins (30 & 87) which switch power
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