Drawer

Circuits

20 sheets in this drawer.

  1. Screw terminals that won't spin your wirePhoenix-style pluggables beat terminal blocks when you rewire in the field. Choose the right pitch and wire gauge before your prototype becomes permanent.
  2. Heatsink compound before the thermal runawayThermal interface material isn't optional when your regulator dissipates real watts. Apply it correctly or watch your voltage sag under load.
  3. Zener clamps when the input surprises youA simple front-end circuit that stops overvoltage from becoming a weekend autopsy.
  4. Analog filtering when the ADC sees every bounceA small RC lowpass between sensor and converter often saves more code than it costs in parts. Here's how to size it without trial and error.
  5. Soft-start circuits when you want the relay to liveInrush current kills relays and trips breakers in home lab power supplies. A simple soft-start circuit spreads that surge over a few milliseconds and saves you from ordering replacements.
  6. Reverse polarity protection you'll thank yourself forA single diode or MOSFET can save your board from a backwards barrel jack. Here's how to pick the right topology without burning half a watt.
  7. LDO headroom when your wall wart driftsLow-dropout regulators promise clean rails, but only if you leave them enough input voltage when your adapter sags under load. Here's how to spec the margin you actually need.
  8. Bulk capacitor math that fits your drawerYou don't need a warehouse of every capacitor value. Three well-chosen bulk caps will cover most low-frequency ripple work if you know the trade-offs.
  9. Test points you'll probe without the regretBare pads on a prototype are archaeology by the second revision. Plan test access when the schematic is still warm.
  10. Solder mask clearance you'll measure onceThe gap between copper and mask determines whether your board survives assembly or becomes a bridging lesson. Here's how to spec it without the rework.
  11. Fuse selection before the smokeFast-blow versus slow-blow matters when your weekend build decides to pull three times its nominal current. Pick the fuse that protects the board, not your assumptions.
  12. UART baud rates that match what you solderedCrystal tolerances and baud-rate math collide in real hardware. Here's how to pick speeds that won't drift into garbage frames.
  13. Inrush current limiting you won't regret at 3 a.m.Your bench supply clicks off when the project powers up, and suddenly Saturday is a troubleshooting session. A few cents of NTC thermistor or series resistance can save the evening.
  14. Pull-up resistors that won't lie to your microcontrollerWeak internal pull-ups work until they don't. Here's how to pick external resistors that keep your I²C lines honest and your GPIO reads predictable.
  15. ADC reference voltage you won't second-guessPick a stable voltage reference once and your analog reads stay honest. Here's how to choose one that survives your bench and your production run.
  16. Decoupling caps where the datasheet actually wants themBypass capacitors aren't optional decoration. Place them right or watch your rails bounce when the load steps.
  17. Linear regulators when switching feels like overkillWeekend projects don't need buck converters. Sometimes a quiet 7805 and proper heat management are exactly enough.
  18. Thermal relief that won't melt your patienceSpoke connections on your pads aren't cosmetic—they're the difference between a joint that flows in three seconds and one you curse for thirty.
  19. Interrupt-driven sensor reads you'll debug oncePolling burns cycles and misses edges. Interrupt-driven sensor reads give you precision timing and lower power draw—if you set them up correctly the first time.
  20. Power the weekend like it mattersA fragile rail is not a character trait. It is unfinished work.