ElectroLab AICookbook

Circuit cookbook

Reusable circuit blocks you can actually recognise.

Browse common subcircuits, see the current path, learn where to probe, and jump into the matching lesson, calculator, or build.

Safety first, always.

ElectroLab AI teaches theory, low-voltage electronics, and planning concepts. Mains voltage, switchboards, fixed wiring, high-current systems, and legal electrical work must only be performed by licensed electricians where required.

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Power block

LED current limiter

Uses a resistor in series with an LED so current stays inside the LED rating.

Reusable subcircuit
5Vcurrent limiterLED load

Use it when

Any indicator LED, optocoupler input, simple alarm light, or status lamp needs predictable current.

Test point habit

Measure voltage across the resistor, then calculate current with I = V / R.

Common trap

Putting the LED straight across the supply and hoping the supply resistance saves it.

Parts in the block

1

DC source

2

series resistor

3

LED

4

return wire

Cookbook circuits are for theory, low-voltage electronics, and supervised bench practice. Mains voltage, fixed wiring, switchboards, and legal electrical work belong with licensed electricians where required.