Jaycar Electronics Catalogue - 23/06-30/09/2022 (Page 219)

hardcore electronics voltage regulators fixed voltage regulators used to maintain a constant voltage metal back metal back 78xx 1a vin gnd mains electricity is dangerous and can cause electrocution or death only qualified electricians can work with voltages above 50vac variable voltage regulators 3.3ω 1w filter cap 79xx 1a vin all prices are in australian dollars increasing the output current of the regulator series pass power transistor the pass transistor must be mounted on a heatsink vout 0.33μf out gnd com +5v +vout gnd data - active components variable power supply using an lm317 voltage regulator regulators like the 7805 can be made to give a higher output voltage vr normal regulated output vb amount by which regulator is boosted above vr vout regulator r1 r2 to make a variable regulator use a pot as r2 +vin gnd vin filter cap gnd bypass vin variable power supply using an lm317 voltage regulator and r2 basically form a voltage divider across the output voltage manufaturer's datasheets tell us that hte regulator needs a nominal 10μf tantalum or equivalent dc source voltage will minimise the dissipation diodes protect the ic from short circuits at vout or vin in 78xx or practical limitations prevent this from happening at full current kª excessive when vin exceeds vout by more than 13v at 1.5a out com vout +vout gnd 1μf tantalum or equivalent +vout gnd