R C HALF WAVE FIRING CIRCUIT Circuit diagram 12 Connection Diagram for RC Half

# R c half wave firing circuit circuit diagram 12

This preview shows page 17 - 23 out of 75 pages.

R-C HALF WAVE FIRING CIRCUIT: Circuit diagram : 12 Connection Diagram for RC Half wave Firing Circuit : PROCEDURE: 1) Make the connections as given in the circuit diagram. 2) Connect a Resistance of 50 ohms between the load points. 3) Vary the control pot(R) and observe the voltage waveforms across load, SCR and at different points of the circuit. 4) Note down the output voltage across the Load for different values of firing angle in degree. 5)Calculate the theoretical and practical output voltage. 6) Draw the graph for input wave form, output waveforms across SCR and Load. TABULAR COLUMN : Sl no. Firing Angle Load Voltage Theoretical [Vm/2 ( 1 +cos ) In Volts Practical in Volts 13 VARIOUS WAVEFORMS FOR RC HALF WAVE CONTROL Wave forms across Input and load: Wave forms across Load and SCR: Firing Angle = X/Y 180 V in V load V load Vscr 14 RC FULL WAVE FIRING CIRCUIT Circuit diagram: Connection Diagram for RC Full wave Firing 15 PROCEDURE : 1) Make the connections as given in the circuit diagram. 2) Connect a Rheostat of 100 ohms between the load points. 3) Vary the pot and observe the voltage waveforms across load, SCR and at different points of the circuit. 4) Note down the output voltage across the Load for different values of firing angle in degree. 5)Calculate the theoretical and practical output voltage. 6) Draw the graph for input wave form, output waveforms across SCR and Load. VARIOUS WAVEFORMS FOR RC FULL WAVE CONTROL: Wave forms across Input and load: Wave forms across Load and SCR: RESULT:- Half and full wave R & RC triggering circuit have been rigged up and output waveforms have been plotted. V in V load V scr V load 16 Experiment No: 04 Date: HALF AND FULL WAVE RECTIFIER USING UJT FIRING CIRCUIT AIM: To study the static characteristics of RC Half and Full wave firing circuit . APPARATUS: UJT Firing circuit Study unit Theory: UJT is highly efficient switch. The switching time is in the range of nanoseconds. Since UJT exhibits negative resistance characteristics it can be used as relaxation oscillator. The circuit diagram is as shown with R 1 and R 2 being small compared to R B 1 and R B 2 of UJT. When V BB is applied, capacitor ‘C’ begins to charge through resistor ‘R’ exponentially towards V BB . During this charging emitter circuit of UJT is an open circuit. The rate of charging is 1 RC . When this capacitor voltage, which is nothing but emitter voltage, V E reaches the peak point V P   V BB V D , the emitter base junction is forward biased and UJT turns on. Capacitor ‘C’ rapidly discharges through load resistance R 1 with time constant 2 R 1 C . When emitter voltage decreases to valley point V v , UJT turns off. Once again the capacitor will charge towards V BB and the cycle continues. The resistor R in the circuit will determine the rate of charging of the capacitor. If R is small the capacitor charges faster towards V BB and thus reaches V P faster and the SCR is triggered at a smaller firing angle. If R is large the capacitor  #### You've reached the end of your free preview.

Want to read all 75 pages?

• Summer '16
• Rectifier, SCR
• • •  