Dimmer Circuit | lamp dimmer Circuit with LM555 and TIP2955

This circuit is DC Dimmer Circuit. By use IC LM555 be model Astable Multi vibrator. It is can change translate Duty Cycle with fining VR1 and VR2 be formed fine brightness level that want.

Mains LED | Mains operated LED lamp Circuit

This is a very simple and cost effective mains operated LED lamp which gives a very bright white light.Since no transformer is used, the circuit is very compact and light weight.The mains supply is given to the bridge rectifier via the parallel network formed between R1 and C1.

Mains High and Low Voltage Protector Circuit, Using IC LM 324

The inclusion of op amps makes the circuit operations much accurate and tripping points adjustable to any levels as desired by the user.
As shown in the figure, we can see two OP amps from the IC LM 324 are used for the required detection.

Refer circuit diagram

 The upper op amp has its non inverting input rigged to a preset and is terminated to the supply DC voltage, pin #2 here is provided with a reference level, so that as soon as the potential at pin #3 goes above the set threshold (by P1), the output of the op amp goes high.

Quite similarly the lower op amp is also configured for some voltage threshold detection, however here the pins are just reversed, making the op amp output go high with low voltage input detection.

Therefore, the upper op amp responds to high voltage threshold and lower op amp to low voltage threshold.
For both the detections, the output of the respective op amp becomes high.

Diodes D5 and D7 make sure that their junction produces a common output from the op amp output pin outs. Thus whenever any one of the op amp output goes high, it is produced at the junction of  D5, D7 cathodes.

Voltage Stabilizer | High / Low Voltage Cutoff Circuit With Timer

This inexpensive high / low voltage cutoff circuit can be connected to an air-conditioner/fridge or to any other sophisticated electrical appliance for its protection. Generally, costly voltage stabilizers are used with such appliances for maintaining constant AC voltage. However, due to fluctuations in AC mains supply, a regular ‘click’ sound in the relays is heard. The frequent energization /DE-energization of the relays leads to electrical noise and shortening of the life of electrical appliances and the relay/stabilizer itself. The costly yet fault-prone stabilizer may be replaced by this inexpensive high-low cutout circuit with timer.

The circuit is so designed that relay RL1 gets energized when the mains voltage is above 270V. This causes resistor R8 to be inserted in series with the load and thereby dropping most of the voltage across it and limiting the current through the appliance to a very low value. If the input AC mains is less than 180 volts or so, the low-voltage cut-off circuit interrupts the supply to the electrical appliance due to energisation of relay RL2. After a preset time delay of one minute (adjustable), it automatically tries again. If the input AC mains supply is still low, the power to the appliance is again interrupted for another one minute, and so on, until the mains supply comes within limits (>180V AC).

AC voltage Stabilaizer | Automatic AC voltage Stabilaizer circuit

Mains Pulser Circuit

The pulsar is intended to switch the mains voltage on and off at intervals between just under a second and up to 10 minutes. This is useful, for instance, when a mains-operated equipment is to be tested for long periods, or for periodic switching of machinery. Transformer Tr1, the bridge rectifier , and regulator IC1 provide a stable 12V supply rail for IC2 and the relay. The timer is arranged so that the period-determining capacitor can be charged and discharged independently. Four time ranges can be selected by selecting capacitors with the aid of jumpers. Short-circuiting positions 1 and 2 gives the longest time, and short-circuiting none the shortest.