DC Board DRC Fixes
Worked for 2 mins 24 sec
Dangling trace cleanup is complete.
- Found 31 dangling-trace warnings.
- Deleted 60 trace stub nodes tied to those warnings.
- Re-ran dangling-trace DRC at 2026-05-15 22:12:22 UTC.
- Remaining dangling traces: 0
No schematic edits or connector moves were made.
Check the layout for unrouted nets after removing those stubs.
Thought for 13 sec
I’ll check the layout for unrouted nets by running the airwire DRC now, then I’ll report the current unrouted count and affected items without making routing changes.
Worked for 32 sec
Layout check found 33 unrouted airwire errors after the overlap and dangling-stub cleanup.
Current cleanup status:
- Overlapping copper: cleared to 0
- Dangling traces: cleared to 0
- Unrouted nets / airwires: 33 errors remain
Next step is routing those remaining airwires, preferably in phases: power/ground first, then signals.
Route power/ground
List unrouted nets
Recheck after routing
Route short signals
Refine this doc
Ask about this doc
Design Notes — 9V 555 LED Blinker
Requirements
- Power from a 9V block battery.
- Battery positive passes through an on/off switch before powering the circuit.
- Blink a red LED approximately once per second.
- Use easy-to-hand-solder parts.
Selected topology
- U1: NE555P DIP-8 timer in astable mode.
- J1: Keystone 967 through-hole 9V battery snap connector.
- S1: Through-hole SPST toggle switch.
- LED1: 5mm through-hole red LED.
- R1, R2: Yageo CFR-25JB-52-47K through-hole 47 kΩ axial resistors.
- R3: Yageo CFR-25JB-52-1K through-hole 1 kΩ axial resistor.
- C1, C2, C3: through-hole capacitors.
Timing calculation
For the standard 555 astable circuit:
Chosen values:
- R1 / RA = 47 kΩ
- R2 / RB = 47 kΩ
- C1 = 10 µF
Result:
This is approximately 1.02 Hz, close to one blink per second.
LED current limit
R3 = 1 kΩ limits LED current from the 555 output to a comfortable indicator current. With a red LED around 2 V and a 9 V supply, expected current is roughly 6–7 mA depending on the 555 output high voltage.
Connectivity summary
- J1 POS → S1 COM.
- S1 NO → VCC_SW_9V rail.
- VCC_SW_9V → U1 VCC, U1 RESET, R1 P1, C3 P1.
- J1 NEG → GND.
- U1 GND, C1 P2, C2 P2, C3 P2, LED1 K → GND.
- R1 P2 / R2 P1 / U1 DISCH → TIMER_DISCH.
- R2 P2 / C1 P1 / U1 THRES / U1 TRIG → TIMER_RC.
- U1 CONT / C2 P1 → CTRL_BYPASS.
- U1 OUT → R3 → LED1 A.
Review
Electrical review found no schematic connectivity issues in the completed blinker circuit. Remaining airwire findings are PCB-layout routing items expected before placement/routing is complete.
Requirements
Selected topology
Timing calculation
LED current limit
Connectivity summary
Review
