• 1:45 The 9-0-9 wire connection to the card for line in
  • 2:08 Transformer other wire connection (Which will act as ground)
  • 3:08 Relay connection to card

Can a manual stablizer hi and lo cut can be created in two such ways
1- here the no point will be active for output and when the hc lc occurs the pcb card will cut the relay volts so that it will be in nc point will be cut
2- here the nc point will be active for output and when the hc lc occurs the pcb card will activate the relay so that it will be in no point and output will be cut

Answer-

Short answer: yes, both schemes work—but #1 is the safer, industry-standard way.

Here’s why and how:

Option 1 — Energize-to-RUN (fail-safe) → Recommended

  • Normal voltage: Control PCB energizes the relay coil → contact moves to NO, load gets power.

  • High/Low cut, control power loss, or PCB failure: Coil de-energizes → relay falls back to NC (open to load) → output is cut.

  • Pros: Fails safe on most faults (sensor/MCU supply failure, broken coil drive, etc.). Meets typical appliance safety practice.

  • Cons: Coil consumes power during normal operation; brief brownouts will trip it (usually what you want).

Option 2 — De-energize-to-RUN

  • Normal voltage: Coil off, output fed via NC.

  • High/Low cut: PCB energizes coil to flip to NO (open) and cut output.

  • Pros: Zero coil power in normal state.

  • Cons: Not fail-safe—if the PCB loses power or the coil driver fails, the load stays ON. Generally avoided for cut-off protection.

Control PCB tips (works for either scheme)

  • Sensing & thresholds: Use a small SMPS or capacitive dropper + resistor divider into a comparator/MCU. Add hysteresis so it doesn’t chatter (e.g., ~5–10 V gap around cut thresholds).

  • Delays: Add turn-off immediate, turn-on delay 5–10 s after voltage returns to normal (prevents rapid cycling).

  • Snubbers: RC snubber or MOV across relay contacts; diode across coil (or RC if using AC coil/triac driver).

  • Relay choice: Use a relay with adequate contact rating (AC-1/AC-15) and surge handling. For many stabilizers 16–30 A relays are typical.

  • Poles: In many designs only phase is switched. For extra safety, consider DPST/DPDT to switch both phase and neutral (follow local code).

  • Thermal & clearance: Keep mains creepage/clearance, fit a thermal fuse near transformer/series elements.

Bottom line

Implement the high/low cut as “energize-to-run” (Option 1) so that any loss of control power or fault disconnects the load automatically. Option 2 is functional but not fail-safe and is generally discouraged for protection cut-outs.

If you want, tell me your target cut thresholds (e.g., cut below 170 V, above 260 V for 230 V systems), relay coil voltage, and I’ll sketch a full parts list and comparator/MCU logic.

Ok can i add buzzer and red led in option 1 in stablizer so when the hc lc occurs the customer will know

Answer-

Yes—totally. In Option 1 (energize-to-run) you can add a buzzer + red LED so they turn on whenever HC/LC triggers (i.e., when the relay coil is de-energized and output is cut).

Here are two clean ways to do it:

A) Drive from the PCB “FAULT” signal (best)

  • Your comparator/MCU already decides HC/LC and de-energizes the relay. Use that same FAULT line to switch a low-voltage buzzer and LED.

  • Keep everything isolated and low-voltage (e.g., 12 V DC from the control supply).

Typical hookup (12 V control rail):

  • LED: +12 V → 1 kΩ → Red LED → NPN transistor collector → NPN emitter to GND.

  • Buzzer (active 12 V type): +12 V → Buzzer → NPN collector → NPN emitter to GND.

  • Driver: FAULT → 4.7 kΩ → NPN base, with 10 kΩ base-to-GND. (2N2222/BC547 etc.)

  • Add a mute switch in series with the buzzer only (so LED still indicates fault if user mutes sound).

  • If relay coil is DC and you use a flyback diode, keep it only on the coil (not on the buzzer).

Behavior: When FAULT goes high (HC/LC), relay drops out, LED + buzzer turn ON. When voltage returns and your reconnect delay expires, FAULT goes low, LED/buzzer turn off and relay energizes.

B) Use the relay state (no firmware change)

If you don’t want to touch logic, use an auxiliary contact (or a tiny second relay) that changes state when the main coil is energized.

  • Put a small SPDT auxiliary relay coil in parallel with the main relay coil.

  • Wire its NC contact to feed the LED/buzzer from the 12 V control rail.

  • Result: When the main coil is energized (normal), aux relay pulls → NC opens → LED/buzzer OFF.
    When HC/LC occurs (coils de-energize), NC closes → LED/buzzer ON.

Don’t ever run the buzzer/LED from mains. Keep them on the isolated low-voltage control side.

Practical tips

  • Buzzer type: Use an active 12 V buzzer (has built-in oscillator). If using a passive piezo, drive it with a small square-wave from MCU.

  • LED resistor: 1 kΩ at 12 V is fine (≈8–10 mA for bright red). Go 2.2 kΩ if you want it dimmer/cooler.

  • On-time & nuisance beeps: You can gate the buzzer with the same reconnect delay so it only sounds during fault and stays silent during the post-restore delay; or add a one-shot (e.g., 1–3 s beep) using an RC to avoid continuous noise.

  • Brownouts/blackouts: If the entire control supply collapses, nothing can drive the buzzer. If you want a short “power-fail chirp,” add a small reservoir cap (e.g., 470–1000 µF) and an RC edge detector so the buzzer blips as the supply falls.

  • Labeling: Mark the LED “HC/LC CUT” so users know why it’s off.

If you share your control voltage (5 V/12 V) and whether your relay coil is AC or DC, I’ll give you exact part numbers and a tiny schematic with values.