Comments on: Short circuit protection relay circuit fail https://www.epanorama.net/blog/2020/08/23/short-circuit-protection-relay-circuit-fail/ All about electronics and circuit design Sat, 04 Apr 2026 05:54:14 +0000 hourly 1 http://wordpress.org/?v=3.9.14 By: Tomi Engdahl https://www.epanorama.net/blog/2020/08/23/short-circuit-protection-relay-circuit-fail/comment-page-1/#comment-1862702 Tue, 30 Sep 2025 21:18:02 +0000 https://www.epanorama.net/blog/?p=186677#comment-1862702 How does this circuit protect against overload? Connect the input to big battery. Connect output to few meters of cable to too high load or short circuit. The result is burned relay and wiring.

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2020/08/23/short-circuit-protection-relay-circuit-fail/comment-page-1/#comment-1850463 Thu, 03 Apr 2025 09:21:15 +0000 https://www.epanorama.net/blog/?p=186677#comment-1850463 it just senses if the input voltage dropped or not. If connected to “weak” power supply that drops voltage when overloaded, can seem to work. If wired directly to battery, will not protect and burn up on overload or short circuit.

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2020/08/23/short-circuit-protection-relay-circuit-fail/comment-page-1/#comment-1772744 Tue, 21 Jun 2022 09:54:16 +0000 https://www.epanorama.net/blog/?p=186677#comment-1772744 ONE FATAL FLAW: the “no power” LED (RED) and relay coil will KILL A ** BATTERY ** in Very Short Order. Therefore, it’s best used with a “wall wart” or similar AC-powered DC power supply.

https://www.youtube.com/watch?v=K-sh91ddCNc

]]> By: Tomi Engdahl https://www.epanorama.net/blog/2020/08/23/short-circuit-protection-relay-circuit-fail/comment-page-1/#comment-1740574 Sat, 20 Nov 2021 09:10:54 +0000 https://www.epanorama.net/blog/?p=186677#comment-1740574 it works somewhat on some usage situation and fails to work on many cases. This is not reliable protection.
This circuit trips only if short circuit causes the voltage on circuit power input to drop enough by short circuit. If you have power supply where voltage does not drop with even high load, this circuit will not trip at all. For example when circuit is wired with short thick wires to car battery, the short circuit on output will most probably melt the thinner wires there and/or the relay on circuit will melt.

]]> By: Nisha Batel https://www.epanorama.net/blog/2020/08/23/short-circuit-protection-relay-circuit-fail/comment-page-1/#comment-1689840 Tue, 01 Sep 2020 10:32:30 +0000 https://www.epanorama.net/blog/?p=186677#comment-1689840 Nice and wonderful blog, great work.

]]> By: Varun Sharma https://www.epanorama.net/blog/2020/08/23/short-circuit-protection-relay-circuit-fail/comment-page-1/#comment-1688911 Mon, 24 Aug 2020 09:51:50 +0000 https://www.epanorama.net/blog/?p=186677#comment-1688911 Nice article. Keep it up.

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