555 Timer Astable/Monostable Calculator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t3-006

Effect

Computation or source lookup only

Input and validation requirements

The zero-resistance astable input produces undefined frequency and duty cycle, so the calculator must validate the denominator and reject the input rather than emit Infinity or NaN. Unitless component values also produce a 1000-fold frequency discrepancy unless the unit convention is explicit.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "mode": "astable",
    "R1_ohm": 1000,
    "R2_ohm": 10000,
    "C_F": 1e-7
  },
  "expected_outputs": {
    "f_Hz": 685.7142857,
    "duty_cycle_fraction": 0.5238095,
    "duty_cycle_percent": 52.38095
  },
  "working": "R1+2R2=1000+2(10000)=21000 ohm. C=100 nF=100 x 10^-9 F=1.0 x 10^-7 F. (R1+2R2)C=21000 x 1.0 x 10^-7=0.0021 s. f=1.44/0.0021=685.7142857 Hz. Duty cycle=(R1+R2)/(R1+2R2)=(1000+10000)/21000=11000/21000=0.5238095=52.38095%."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche3/tranche3-results.json