Emergency Light 555

Emergency Lamp With 555 is one solution for lighting during power outages. With Emergency Lamp Series 555 uses a 12VDC voltage source that can be supplied from the 12V battery. Emergency Lamp 555 Series With these very simple and easy to make because all the components easily available in the market. Emergency Lamp Series With this 555 can turn on the light 5W-10W. The circuit is built with an astable multivibrator with the IC 555 that is used to mendrive transformer through Q1. For more details can be viewed directly from the series Emergency Lamp With 555 follows.

Working frequency range of 555 Emergency Lamp With this set of configurations R1, R2 and C2. T1 in series Emergency Lamp With 10V 500mA 555 is a transformer. Secondary part (0-10V) is connected to the Q1 to be given the signal from the multivibrator. Then the primary (0-220V) is connected to the lamp.

Read More

Voltage Controlled Switch using 555 Timer descroption and circuit

Notes:
The old and omnipresent NE555 can be very good at something it was not meant for: driving relays or other loads up to 200 mA. The picture shows an example circuit: if the input level rises over 2/3 of the supply voltage - it will turn on the relay, and the relay will stay on until the level at the input drops below one third of the supply voltage.

If the relay and D1 were connected between pin 3 and ground, the relay would be activated when the input voltage drops below one third, and deactivated when the input voltage goes over two thirds of the supply voltage.

It is also a nice advantage that the input requires only about 1 uA, which is something bipolar transistors cant compete with. (This high impedance input must not be left open.) A large hysteresis makes the circuit immune to noise. The output (pin 3) can only be either high or low (voltage-wise), and it changes its state almost instantenously, regardless of the input signal shape.

The voltage drop across the NE555s output stage (at 35-100 mA) is 0.3-2.0 V, depending on the way the relay is connected and the exact current it draws. D1 is absolutely vital to the safety of the integrated circuit.Source :: http://www.zen22142.zen.co.uk/Circuits/Switching/vcs555.htm
Read More

Police Lights Circuit with 555 and 4017 IC

This circuit uses a 555 timer which is setup to both runn in an Astable operating mode. This generates a continuous output via Pin 3 in the form of a square wave. When the timers output changes to a high state this triggers the a cycle on the 4017 4017 decade counter telling it to output the next sequential output high. The outputs of the 4017 are connected to the LEDs turning them on and off.

Police Lights Circuit Schematic

Read More

Relay Toggle Circuit Using a 555 Timer

This 555 timer circuit below toggles a relay when a button is pressed. Pins 2 and 6, the threshold and trigger inputs, are held at 1/2 the supply voltage by the two 10K resistors. When the output is high, the capacitor charges through the 100K resistor, and discharges when the output is low. When the button is pressed, the capacitor voltage is applied to pins 2 and 6 which causes the output to change to the opposite state. When the button is released, the capacitor will charge or discharge to the new level at the output (pin 3). The parts are not critical, the resistors can be somewhat higher or lower, but the 2 resistors at pins 2 and 6 should be equal values, and the resistor connected to the cap should be 10 times greater or more.

Circuit diagram :

Relay Toggle Circuit Diagram

Advantages of this circuit are the large hystersis range at the input which avoids false triggering, and only a few parts are needed for construction. One disadvantage is the relay may be engaged when power is first applied. To solve this problem, you could tie the reset line (pin 4) to another resistor/capacitor combination with the capacitor at ground and the resistor at the +V point. This will cause pin 4 to be held near ground for a short period which will reset the output when power is applied.

The 100 ohm resistor and 100uF capacitor serve to filter noise on the supply line if the circuit is used in a automotive application. They may not be necessary. The circuit may work well without those parts.

Read More