Light Dimmers

Triac mains light dimmer

This is the schematic of the conventional light dimmer. L1 and C2, C3 form the lichtnetontstoring. In this circuit meets almost every TRIAC as a TIC226D. For C1, C2 and C3 good capacitors (MKT example) with a minimum operating voltage of 400V. ..

Lamp Dimmer schematic

The full wave phase control circuit below was found in a RCA power circuits book from 1969. The load is placed in series with the AC line and the four diodes provide a full wave rectified voltage to the anode of a SCR. Two small signal transistors are connected in a switch configuration so that when the voltage on the 2.2uF capacitor reaches about 8 volts, the transistors will switch on and discharge the capacitor through the SCR gate causing it to begin conducting. The time delay from the beginning of each half cycle to the point where the SCR switches on is controlled by the 50K resistor which adjusts the time required for the 2uF capacitor to charge to 8 volts. ..

AC lamp Dimmer Schematic

The circuit is directly connected to the AC power line and should be placed inside an enclosure that will prevent direct contact with any of the components. To avoid electrical shock, do not touch any part of the circuit while it is connected to the AC power line. A 2K, 10 watt power resistor is used to drop the line voltage down to 9 volts DC. This resistor will dissipate about 7 watts and needs some ventilation. In this circuit, an SCR is used to slowly vary the intensity of a 120 volt light bulb by controlling the time that the AC line voltage is applied to the lamp during each half cycle. ..

12 Volt Lamp Dimmer schematic

Here is a 12 volt / 2 amp lamp dimmer that can be used to dim a standard 25 watt automobile brake or backup bulb by controlling the duty cycle of a astable 555 timer oscillator. When the wiper of the potentiometer is at the uppermost position, the capacitor will charge quickly through both 1K resistors and the diode, producing a short positive interval and long negative interval which dims the lamp to near darkness. ..

Advanced Light Dimmer

This circuit is a real core of the dimmer system. This circuit generates ramp 100 Hz signal which is syncronized to the incoming mains voltage. The ramp signal which is generated will start form 10V and go linearly down to 0V in 10 milliseconds. At the next mains voltage zero crossing the ramp signal will again immediatly start from 10V and go down to 0V. This same ramp signal is fed to all of the 4 comparators in the dimmer. The following ramp signal generator is quite simple ramp generator based on discrete transistors which do some switching, capacitor and a constant current source made by using one transistor. ..

Car Light Dimmer 12 Volt

This unique circuit makes your dome light look cool. Usually when the car door is closed, the dome light just goes OFF. With this circuit, you can have our dome light fade slowly in brightness and finally go OFF. This slow dimming of the light gives a very good feeling at night. It looks very romantic! The circuit can be explained as follows: When the car door is open, the push to off switch of the door is ON and hence it charges the 22uF capacitor fully. The opamp is acting as a voltage follower and its output is same as the voltage across the capacitor, which is 12V when the capacitor is fully charged. Due to a high voltage at the output of the IC, the transistor saturates, turning ON the bulb to full brightness...

20 Watt Halogen Light Dimmer

Microprocessor control of one 20 watt halogen lamp. Three power levels (7 / 10 / 20 watts). Single pushbutton control for on/off and power level. The PIC16F84 chip is re-programmable, allowing unlimited changes to the basic code. Connect a 12 volt 20 watt lamp and 12 volt battery to the circuit (observe battery polarity). Momentarily press and release the button to turn the lamp on. Repeatedly press the button to cycle through the power levels. Pressing and holding the button will turn the lamp off...

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. ..

Mains Light dimmer

A simple mains Light dimmer...

12 Volt Dimmer control

This circuit uses an MC3392 low side protected switch and an MC1455 timing circuit to form an automotive instrumentation panel lamp dimmer control. The brightness of incandescent lamps can be varied by Pulse Width Modulating the input of the MC3392. The modulating signal can be obtained directly from the MC1455 timer (or a microprocessor). The MC1455 is configured as a free-running clock having a frequency and duty cycle control. The typical timer frequency is approximately 80 Hz when the frequency potentiometer is adjusted to 1.0k. This frequency was chosen so as to avoid any perceptible lamp flicker. ..

Touch Light Dimmer circuit

With this circuit we can change the brightness of lamb, with a only key of touch. The key of touch is connected in the circuit, center of which is a special completed IC1, which is the S566B of SIEMENS. This IC, it processes the information of duration of touch and then it checks the brilliance of lamb, according to this information. If we touch upon the key for a small period of time (60 until 400 ms), the lamb simply only changes situation, that is to say from OFF in ON or on the contrary, depended from the situation is found itself before the unit. In one of bigger duration of touch (more from 400ms), is altered the brilliance of lamb, late from dark in luminous or on the contrary. Are required roughly seven seconds, in order to we have complete brilliance. ..

Car central Light Dimmer

A useful operation for the cars is delayed extinguishing internal lighting cabin of passengers, after close some door of car. Certain cars allocate this operation from their constructor. Oldest sure do not allocate such operation. This delay makes this circuit. In the scheme appears the delay circuit as well as a typical circuit of connections of lamp L1, usually 12V 10W, with the switch S1 choice of lamp operation. In place A the lamp L1 remains continuously turned on, because the switch is in the place of 0V. In place B the lamp it remains off and in place C the lamp it turns on and she remains turned on all hour some door is open, hence somebody from the switches that are found in each door have closed have given the 0V in the lamp. If now the door close, the corresponding switch go open, but the C1 is already charge, discharge by the Q1 and makes the Q4 close...

Current Dimmer for white 24 LED array

This simple Linear circuit provides continuously variable regulated current (~25-400mA) from a 4-6 Volt source. I chose a linear design for simplicity, reliability, ease of repair, and to avoid switching EMI in my Cave Radios. The circuit requires only 0.2V headroom above the parallel LED Array voltage to provide regulation at maximum current. The headroom stays low until the LED's are extinguished at about 0.75V/cell for 4-cell packs. End of life for alkalines is usually considered to be 0.9V/cell. My HDS 24-LED array requires 2.9V at 25mA and 3.5V at 440mA. ..

Lamp Dimmer / Motor Speed Control

The diac is a common component used to trigger triacs. The construction of a diac is similar to that with a transistor, but with both junctions doped to similar levels so that the two junctions' revers break down characteristics are similar. This is a fun project to demonstrate the use of a pair of bipolar transistors operating in their negative resistance region to simulate a diac triggering a triac in an incandescent lamp dimmer. The circuit is not optimized for performance -it is only intended to demonstrate the principle...

This little circuit can be used to dim lights up to about 350 watts. It uses a simple, standard TRIAC circuit that, in my expirience, generates very little heat. Please note that this circuit cannot be used with fluorescent lights...