Dusk To Dawn Circuit Evaluation (Non-Darlington Version)

00:00 - Intro
02:10 - Trouble shooting Initial Connection Issues
06:45 - Total current through the battery measurements
09:22 - Current through R1 (bottom current mirror setting)
12:00 - Current coming for the transistor side of the mirror
13:55 - I determine that I started with the wrong PCB
14:20 - Current from the photoresistor side of the circuit
15:10 - Quick Explanation of what is happening with the removal of the shorts (creating open circuits)
16:10 - Discovery of the first 0uA point. Through photo-resistor side of circuit.
17:40 - Quick aside about how one side hogs the current from the other.
18:10 - Quick look at the schematic
18:35 - Current through the LED and set voltage side (LED is on without darkness too!)
20:30 - Analyzing current out of the base of the 'LED On' transistors
20:45 - Pulling the short (creating open circuit) will result in the LED never turning on!
23:25 - Current through the LED
25:03 - Concluding Remarks

Did my dusk-to-dawn circuit work as expected?

In this video, I analyze the results from my PPK2 evaluation of a differential amplifier circuit controlled by a photoresistor. Sometimes I got surprised by the lack of current in areas (complete zero at times). Othertimes I was surprised by the effect of making an open circuit in the circuit.

The KiCAD files can be found here: https://github.com/PhysicsUofRAUI/lao...

This circuit, based on "The Art of Electronics" (page 124), is designed to turn an LED on and off based on light levels.

Stayed tuned for future videos where I will be showing the darlington pair version and one where I add extra test ports.

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