Fluorescent Circuits

12 Neon Lamps Sequencer circuit

This circuit is similar to the LED clock using 12 neon indicator lamps instead of LEDs. It operates from 2 high capacity ni-cad cells (2.5 volts) which keep it going for a couple weeks. High voltage (70 volts) for the neon lamps is obtained from a small switching power supply using a 74HC14 Schmitt trigger squarewave oscillator, high voltage switching transistor, and 10 mH high Q inductor. Most any small PNP transistors can be used that have a C/E voltage rating of 80 or more. The inverter stage (pins 5,6) is not needed and is just an extra stage. ..

Neon Lamp Flashing Schematic

In this circuit, one, two or three neon indicator bulbs can be made to flash in sequence at rates determined by the R and C values. In the single stage circuit, using one lamp, the capacitor charges through the resistor until the ionization potential of the neon is reached (about 70 volts) and then discharges quickly through the lamp until the voltage falls below what is needed to sustain the lamp which is approximately 45 volts. The cycle then repeats at a rate of about 3 Hz for values shown...

Energy Saving Night Light circuit

The lamps are usually used as ballast or electronic ballast inverter. Here it is used to reduce voltage capacitor reactance. Interesting is also the method of ignition of the auxiliary electrodes involved over 150 Ohm resistors. To start simply involve only one, but the lamp is switched on for longer blinks. Filament is not used and are short-circuited. The operation is relatively low-voltage fluorescent tubes, it looks like it worked pretty well and easy to drive on battery power. The drive would only have to load a relatively large supply voltage, or fluorescent lights...

Inverter circuit for florescents

This inverter is very easy to construct, reliable, and even powerful enough to light up a 15W florescent tube (if you cool your transistor well). The only hard-to-find piece of this baby is the so-called yellow inverter transformer. It's a miniature high frequency transformer that has a 25mm x 20mm x 5mm ferrite core, 30 turns of primary, 15 turns of feedback, and 250 turns of secondary all concentric, wound on plastic frame than wrapped with a 'yellow' adhesive tape. If you can't find it in your local electronic shops then search for old portable rechargeble florescent lanterns since they have at least one yellow inverter. ..

12 Volt Fluorescent Lamp circuits

Here is the schematic diagram for a 20 Watt driver. I developed this circuit in 1985, and used it to build a lamp that found much use both as camping light and as emergency light during the then-frequent power outages. The two transistors work as a push-pull oscillator. To avoid crossover conduction, during operation the bases are self-biased to a slightly negative voltage by the 1R5 resistor. The 220uF capacitor gives strong positive bias during power-up, in order to get the oscillator started. 2k2 resistor's only purpose is discharging the capacitor when the circuit is switched off, so it will restart the next time too!..

12 Volt Fluorescent inverter for 20 - 40 Watt tubes

This is a low-cost project for 20 or 40 watt fluorescent tubes. However the most efficient is to use a 40 watt tube (or two 20 watt tubes in series). It's a circuit you can put together from junk box components or build from a kit. It's very simple to build and requires no printed circuit board. The transformer is hand-wound on a ferrite rod (from an old transistor radio) and the winding wire can be salvaged from an old transformer. The ferrite core of the transformer is an antenna rod from an old transistor radio. You could use a slab antenna but we have chosen a 10mm diameter rod, 8cm long and the first winding to be wound on it is called the primary. We are purposely keeping costs down to show how cheaply it can be put together...

Neon Lamp Dimmer circuit

The circuit (before flameout) worked like this: device Q1 is a triac, which is a power-switching device. When triggered, it switches to afully conducting state, and stays that way until the current passingthrough it goes to zero. As it is connected to the alternating current, which changes direction 120 times a second, it will be turned off asoften. The trick to making it "dim" lies in how and when you turn it on. That task is left to components R1, C1, and D1. Assume the following: the alternating voltage applied to the upper black wire in fig. 1 has just (timewise) crossed through zero and is increasing. Current starts to flow through pot R1 (the thing on the other end of the plastic knob) and starts charging up capacitor C1. As you turn the knob clockwise, you decrease the resistance of R1,causing C1 to charge faster. ..

The circuit is based on IC1, which is a 555 timer IC in astable mode. It will power a 6 inch 4 Watt fluorescent tube off a 12 volt supply, consuming 300 mA. It may also be powered by a suitably rated universal AC/DC adapter. Advantages of the design are: good light, low power consumption, and readily available stock parts...

The IR2166 Demo Board is a high efficiency, high power factor, fixed output electronic ballast designed for driving rapid start fluorescent lamp types. The design contains an EMI filter, active power factor correction and a ballast control circuit using the IR2166. This demo board is intended to ease the evaluation of the IR2166 Ballast Control IC, demonstrate PCB layout techniques and serve as an aid in the development of production ballasts using the International Rectifier IR2166...

The design usually involves a compromise between turn-on voltage and lamp life because the two are inversely related. One way to reach a reasonable compromise is to initially allow a momentary inrush current to warm the filaments, followed by a series of interrupted short circuits across the lamp that generate the required high voltage to trigger the fluorescent. With a preheated filament, the necessary strike potential reduces to half...

The circuit shown in Figure 1 has been designed to drive an 8Wfluorescent lamp from a 12V source, using an inexpensive inverter based on the ZTX652 transistor. The inverter will operate from supplies in the range of 10V to 16.5V, attaining efficiencies up to 78% thus making it suitable for use in on-charge systems such as caravans / mobile homes/ RVs as well as periodically charged systems such as roadside lamps, camping lights or outhouse lights etc...

This 40W fluorescent lamp inverter allows you to run 40W fluorescent tubes from any 12V source capable of delivering 3A. This is basically a larger version of the 12VDC Fluorescent Lamp Driver and can be used to light regular or blacklight tubes...

The IR2156 incorporates a high voltage half-bridge gate driver with a programmable oscillator and state diagram to form a complete ballast control IC. The IR2156 features include programmable preheat and run frequencies, programmable preheat time, programmable dead-time, and programmable over-current protection. Comprehensive protection features such as protection from failure of a lamp to strike,filament failures, as well as an automatic restart function, have been included in the design. The IR2156 is available in both 14 lead PDIP and 14 lead SOIC packages...

A number of people have been unable to find the transformer needed for the Black Light project, so I looked around to see if I could find a fluorescent lamp driver that does not require any special components. I finally found one in Electronics Now. Here it is. It uses a normal 120 to 6V stepdown transformer in reverse to step 12V to about 350V to drive a lamp without the need to warm the filaments...

An innovative new strike voltage generation technique enables the module designer to optimize high voltage transformer design for maximum efficiency while the lamp is ignited. The high voltage drop on the output ballast capacitor needed for Royer oscillators is much less, reducing transformer size and power dissipation...