Position: Index > Lamp Circuit >

D_C_SUPPLY_FOR_FLUOURESCENT_LAMPS

2016-08-03 19:14  
Declaration:We aim to transmit more information by carrying articles . We will delete it soon, if we are involved in the problems of article content ,copyright or other problems.


D_C_SUPPLY_FOR_FLUOURESCENT_LAMPS
Lamp operates directly from d-c supply, without a-c conversion. Transistors form constant-current source that controls lamp current. Q3 is controlled by Schmitt trigger Q1.Q2. When lamp current exceeds preset value, voltage drop across 5.6-ohm resistor turns on Q1, thereby turning off Q2 and Q3. When lamp current falls, Q3 comes on again. To start, pushbutton closes circuit through lamp heaters and shunts 5.6-ohm resistor to give faster heating. When button is released, voltage surge caused by series inductor ignites lamp. Control circuit then varies lamp current 25% above and below its average value at 1-kc rate. Regulator losses are only 3 w.-D. B. Hoisington, Direct Current Regulator Drives Fluorescent Lamps, Electronics, 39:17, p 94-95.