Snubbers are the circuits of energy absorption used to smooth the circuit’s inductance voltage spikes. Overvoltage and overheating of the component sometimes fail because of the overcurrent. We use fuses at proper locations for the over-current protection of the circuit, and we use heat sinks or fans for overheating.
We will teach you in this project how a Snubber circuit protects a thyristor from overvoltage or overcurrent. The device consists of a Snubber circuit over the Thyristor and a 555 timer IC frequency generator.
Hardware Component
The following components are required to make Thyristor Switching Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Connecting wires | – | – |
| 2. | Power supply | 9v | 1 |
| 3. | Oscilloscope (for output confirmation) | – | 1 |
| 4. | Switch | – | 1 |
| 5. | IC | NE555 timer | 1 |
| 6. | Diode | 1N4007 | 1 |
| 7. | Thyristor | TYN612 | 1 |
| 8. | Capacitor | 0.1uf, 0.01uf, 0.001uf | 2,1,1 |
| 9. | Resistor | 1k,10k,47k,150 | 1,2,2,1 |
TYN612 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of TYN612
NE555 IC Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of NE555 IC
Thyristor Switching Circuit
Circuit Operation
The circuit consists of two sections. The first circuit is used as a frequency generator circuit utilizing a 555 timer IC whose output is used to power the Thyristor’s gate terminal. The second section of the circuit is used to verify with the Snubber circuit and without the Snubber circuit, for switching the Thyristor or SCR.
The Case I: Without Snubber Circuit
If the Snubber circuit is not present in the SCR as seen in the above circuit, high voltage spikes happen, as you can see in the below waveform. We use a Snubber circuit to smooth the voltage spikes, preventing damage due to overvoltage or the DV/DT device’s false triggering.
The Case II: With Snubber Circuit
When the Snubber circuit is present in the SCR, voltage spikes are reduced or smoothed, as shown in the waveform below. The device is also not damaged because of overvoltage and therefore reduces the dv/dt value of the device as well as the maximum rating.
Applications and Uses
- Snubbers are circuits used in the induction of circuits to absorb energy to smooth the voltage spikes.
- To adjust the voltage or current shift rates, snubber circuits (di/dt or dv/dt) and overvoltage are used, whereas the circuit is ON and OFF.
