curl --request POST \
  --url https://api.iotools.cloud/v1/tool/timer-555-calculator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "mode": "astable",
  "r1": "1",
  "r2": "10",
  "rMono": "10",
  "resistanceUnit": "kohm",
  "capacitance": "1",
  "capacitanceUnit": "uf"
}
'

{
  "tool": "timer-555-calculator",
  "tool_version": "1.0.1",
  "outputs": {
    "summary": [
      {
        "metric": "Frequency",
        "value": "68.7144 Hz"
      },
      {
        "metric": "Period",
        "value": "14.553 ms"
      },
      {
        "metric": "Time High",
        "value": "7.623 ms"
      },
      {
        "metric": "Time Low",
        "value": "6.93 ms"
      },
      {
        "metric": "Duty Cycle",
        "value": "52.38%"
      }
    ]
  },
  "credits_used": 3,
  "credits_remaining": null
}