For school I was assigned a madlab circuit, E-lock, to build and explain how it works, and to be frank, I have no clue how it works. I was able to build it and it functions as it is suppose to: using the frequency of the sounds emitted when you click the numbers on your phone keypad to light up an LED. But when it comes to explaining the different components and how they are used in the circuit, I'm lost. Any help would be greatly appreciated. I'm looking more for the surface-head scratch of how these components function. Component list

  • Resistors
  • Diodes
  • Chips and their sockets
  • Electrolytic capacitors
  • LED
  • XTAL
  • Transistors
  • Regulators
  • Connector
  • Relay
  • MIC
  • Battery

Here's the schematic (above) and the construction sheet (below)


Construction sheet 1

Construction Sheet 3

  • $\begingroup$ Start by reading about HT9170 and 12F629. They are the important parts. No one is expecting you to be an expert, but my brief look at those components gave me a good understanding of what is happening. Couple that with the instructions and you should have some idea! $\endgroup$ – StainlessSteelRat Dec 14 '20 at 19:17
  • 2
    $\begingroup$ Hi Scott, It's an unwritten rule on stack exchange that homework questions without an attempt to solve will be closed. We will help with homework if you show the work you've done, and ask specific questions about the parts you're stuck on. $\endgroup$ – Drew Dec 15 '20 at 22:27

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