4. SCR ACTING AS A SWITCH IN DC AND AC CIRCUITS.doc -...

Rogelio G. Bambalan Jr. Engr. John Ochoco
CEAT-04-502P
MWF/4:30 – 6:00p
SCR ACTING AS A SWITCH IN DC AND AC CIRCUITS
OBJECTIVES :
1. To be familiar with SCR applications.
2. To be able to construct a SCR AC/DC static switch and evaluate its
operation.
3. To demonstrate how high current can be switched with a low power
signal.
MATERIALS :
1 - Resistor, 1K 
1 - Potentiometer, 50K Ω
1 - Silicon-Controlled Rectifier, 2N5060
1 - Switch, SPST
1 - Miniature Lamp, 10 Watts / 12 Volts
1 - Breadboard
1 - VOM
1 - Step-Down Transformer (Multi-Tapped)
1 - Regulated DC Power Supply
1 - Dual-Trace Oscilloscope
PROCEDURES :
1. Construct the experimental circuit as shown in Figure 1.
2. Close the switch. Increase the triggering voltage by adjusting the
potentiometer until the SCR is triggered, the lamp will turn on.
3. Using the VOM, measure and record the triggering current and the
load current in Table 1.
4. Using the oscilloscope, measure and record the voltage drop
across the SCR and the voltage drop across the load. Draw the
waveforms.