Red LED Blinker Circuit Design
Make a circuit that blinks a red LED once per second.
Power it with a 9V block battery through an on/off switch.
Use components that are easy to hand-solder.
Thought for 26 sec
I’ll build a through-hole 555 astable LED blinker for a 9V battery: select hand-solderable parts, calculate ~1 Hz timing, wire the schematic with required 555 bypass/decoupling, then run checks.
Worked for 6 mins 31 sec
Done — I created the through-hole 9V NE555 red LED blinker schematic, added the battery snap and on/off switch, wired the full astable circuit with required 555 bypass/decoupling, and fixed the review issue by assigning MPNs to the passives.
Review is clean: no matching ERC/manufacturing warnings or errors. I also updated Design Notes with the parts, wiring summary, and timing/current calculations.
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Design Notes
Requirements
- Blink a red LED about once per second.
- Powered from a 9V block battery.
- Include an on/off switch.
- Use easy-to-hand-solder through-hole components.
Architecture
- 555 timer in astable mode powered directly from switched 9V.
- Red LED driven from the 555 output through a current-limiting resistor.
- Required 555 support parts included: control-pin bypass capacitor, local 100nF decoupling capacitor, and 10uF bulk capacitor.
Selected Components
- U1: NE555P, DIP-8 through-hole timer.
- BT1: Keystone 967 9V battery snap connector.
- SW1: Through-hole SPST power switch.
- D1: LTL-307EE red 5mm through-hole LED.
- R1: 1kΩ axial resistor, astable charge resistor.
- R2: 680kΩ axial resistor, astable discharge/timing resistor.
- R3: 680Ω axial resistor, LED current limit.
- C1: 1µF radial capacitor, astable timing capacitor.
- C2: 10nF disc capacitor, 555 control-pin bypass.
- C3: 100nF disc capacitor, 555 VCC decoupling.
- C4: 10µF radial capacitor, switched 9V bulk capacitor.
Calculations
- 555 astable frequency with R1 = 1kΩ, R2 = 680kΩ, C1 = 1µF: about 1.06Hz.
- Period: about 0.94s.
- Approximate LED current using 9V supply, ~2V red LED, and estimated 555 high-level drop: about 8.1mA.
- Estimated total switched-rail load: about 15mA peak including NE555 operating current and LED current.
Wiring Summary
- BT1 positive feeds SW1 COM; SW1 NO creates the switched 9V rail.
- U1 VCC and RESET are tied to switched 9V; U1 GND goes to battery negative/GND.
- Astable: R1 from switched 9V to DISCH, R2 from DISCH to the TRIG/THRES timing node, C1 from timing node to GND.
- Pin 5 CONTROL is bypassed to GND by C2.
- C3 and C4 connect from switched 9V to GND near U1.
- U1 OUT drives R3 then D1 anode; D1 cathode returns to GND.
Status
Schematic created and wired. ERC/review results are tracked in the project review panel.
Requirements
Architecture
Selected Components
Calculations
Wiring Summary
Status
