Time Period For UJT As Oscillator Thyristor Firing Circuit Calculator

Formula Used:

\[ T_{UJT(osc)} = R_{stb} \times C \times \ln\left(\frac{1}{1-\eta}\right) \]

Time Period of UJT as Oscillator (T_UJT(osc)):

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1. What is Time Period For UJT As Oscillator?

The Time Period For UJT As Oscillator in Thyristor Firing Circuit represents the time taken by the UJT oscillator to complete one full oscillation cycle. It is a crucial parameter in determining the firing angle and frequency of thyristor-based circuits.

2. How Does the Calculator Work?

The calculator uses the UJT oscillator formula:

\[ T_{UJT(osc)} = R_{stb} \times C \times \ln\left(\frac{1}{1-\eta}\right) \]

Where:

\( R_{stb} \) — Stablizing Resistance (Ω)
\( C \) — Capacitance (F)
\( \eta \) — Intrinsic Stand-off Ratio (dimensionless)
\( \ln \) — Natural logarithm function

Explanation: The formula calculates the oscillation period based on the RC time constant and the intrinsic stand-off ratio of the UJT, which determines the firing point of the oscillator.

3. Importance of Time Period Calculation

Details: Accurate time period calculation is essential for proper thyristor firing control, ensuring correct phase angle control in power electronic applications such as motor speed control, light dimming, and power regulation.

4. Using the Calculator

Tips: Enter stablizing resistance in ohms, capacitance in farads, and intrinsic stand-off ratio (typically between 0.5-0.8 for most UJTs). All values must be valid positive numbers with η between 0-1.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for intrinsic stand-off ratio?
A: The intrinsic stand-off ratio (η) typically ranges from 0.5 to 0.8 for most UJT devices, though specific values depend on the particular UJT model.

Q2: How does stablizing resistance affect the time period?
A: The time period is directly proportional to the stablizing resistance. Increasing Rstb increases the time period, while decreasing it reduces the time period.

Q3: What is the role of capacitance in UJT oscillation?
A: The capacitor charges through the resistance and discharges through the UJT when it fires. The capacitance value directly affects both the charging time and the oscillation frequency.

Q4: Can this calculator be used for different UJT models?
A: Yes, as long as you have the correct intrinsic stand-off ratio value for your specific UJT model, the calculator will provide accurate results.

Q5: What are practical applications of UJT oscillators?
A: UJT oscillators are commonly used in thyristor firing circuits, timing circuits, pulse generators, and sawtooth wave generators in various electronic applications.