The ac line voltage is converted to pulsating dc, by the full-wave diode bridge. This allows the SCR to be triggered “ON”for both half-cycle of the line voltage, which doubles the available power to the load.
1. Rectifier Circuit.
2. Output Wave.
3. SCR Testing.
4. Video Tutorial
In this circuit, the initial voltage from which capacitor C charges is almost zero. Capacitor C is set to this low positive voltage by the clamping action of SCR gate. When the capacitor charges to a voltage equal to Vgt SCR triggers and rectified voltage Edc appears across load. CIRCUIT DIAGRAM:-An RC-Diode circuit giving full half-cycle control (180 electrical degrees). On the positive half-cycle of SCR anode voltage the capacitor charges to the trigger point of the SCR in a time determined by the RC time constant and the rising anode voltage. The top plate of the capacitor charges to the peak of the negative voltage cycle through diode D2 on the negative half-cycle, resetting it for the next charging cycle.
During negative half cycle capacitor charges in reverse direction when the supply voltage increases towards positive side the capacitor voltage also recharges in opposite direction. When this capacitor voltage reaches threshold voltage SCR will turn on and capacitor discharges through diode D2 and its voltage become very small positive voltage. Firing angle can be varied from 0 to 180 degree.
Power can be delivered to the load in Half wave during the positive half-cycle of es because the SCR conducts only when it is forward biased. This limitation can be overcome in several ways. Here, the ac line voltage is converted to pulsating dc. by the full-wave diode bridge. This allows the SCR to be triggered “on”” for both half-cycle of the line voltage, which doubles the available power to the load.