Electronic transformer dims halogen lamp


Posted on Aug 24, 2012

Figure 1 shows a simplified schematic of a typical low-voltage halogen-lamp transformer without the protection circuits and EMI filter. Q1 and Q2 with C2 and C3 comprise a classic, half-bridge topology that works in self-oscillating mode. The circuit provides positive feedback by placing the primary windings of transformer T1 in series with the bridge output. To achieve a high power-factor value, a rectified but unfiltered mains voltage supplies power to the circuit. The working frequency is approximately 30 to 40 kHz.



This simple circuit does not allow for correctly and conveniently dimming the lamp because any attempts to manipulate the time constant of the R1/C1 start-up circuit worsen the power factor. A possible solution that involves making taps in the primary win




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Telephone motor Controller
220V Mains Quality Monitor
Vlf converter
Amplifier-for-signal-supply
high gain antenna 43dB amplifier circuit
Protection For Telephone Line Circuit
PWM to vary the light intensity of a 220V bulb
arduino pulse to transistor power maximum
Block Diagram of the CT Scanner
magnetic tampering
Metal Detector CS209A Circuit
Summing amplifier/ Inverting adder circuit using op amp 741
TDA7000 FM Radio Receiver Circuit
Wide Dynamic Range Field Strength Meter
Alternately flashing lights chain multiple sets of high-power circuit 2
Chizuru 100Hz channel frequency pulse charging electric bike battery circuit



Top