1.5… 4.5V to 9V converter

                      1.5… 4.5V to 9V converter

                       


3 volts to 9 volts with LMC555

This DC converter is constructed using the CMOS version of the 555 timer. You can get too if you change 12V Zener diode to a 12V version.

555 ON/OFF Touch Switch

                                   555 ON/OFF Touch Switch

Components List

R1 = R2 = 3.3M
R3 = 10K
R4 = 1K
C1 = 10nF
D1 = 1N4007
Q1 = BC547
IC = NE555
12V relay

This touch switch ON OFF circuit is based on known timer IC 555 , which actuates a relay which acts as a switch. Metal surfaces may be the way we want, but it must be clean and close the circuit.

Tap plate MP1 in order to close the relay contact RL1 [ON] or MP2 board to open the contact RL1 [OFF]. The D2 LED lights when the contacts of RL1 closed. Two small pieces of metal can be used as sensor plates.

the Water Alarm Circuit

                                       The Water Alarm Circuit

It's just a water sensor, which can be configured as an Alarm Indicator tank overflow alarm rain water leakage from aquarium water, etc. It can be powered from any supply 6VDC. Initially, when the DC power supply circuit, the red LED is off. However, it detects when the presence of water between the detection probes (s1, s2), the LED blinks at a slower pace.

Light sensitive switch

Light sensitive switch

Light sensitive switch with LDR, actually it has a buzzer which will sound .

Police Car Lights circuit

This square wave is damped by IC1b and in turn drives decade counter IC2. The outputs of the counter Q0/Q2 and Q7/Q9 are diode ORed turn to alternating double pulses.

C2 and C3 with R5 and R3 differ pulse time in conjunction with the output drivers and IC1C IC1F. This produces a short pulse (30 ms) increases the effect of flash and adds to the illusion. Output drivers turn drive a pair of blue leds hyperbright D5 and D6.

LEDS Flashing circuit diagram

This simple and inexpensive circuit is not just for Christmas! There are only two resistors, transistor such as a BC547 signal a "flashing" LED and a series of "normal" LEDs. The blinking LED operates as an oscillator and changing the transistor on and off, and the transistor switches all other LEDs. An (non-regulated) Power supply 12 V can be used for power.

No current limiting resistor is required in the LED string, because the forward voltages of the LED in the string is added to the supply voltage. If the red LEDs are used, with a voltage drop of 1.65 V, then 12 V supply seven alternatively, use six five green yellow (2.1 V each) or (2.7 V ). You, of course, you can always mix colors.

Solar garden lights circuit

Solar garden lights circuit

The solar panel  provide 5.5 V and 150 mA. Assuming 3.7V/1500mAH battery charging is complete in 8 hours at 200% capacity at 180 mA. With 10 LED energy consumption would be 90 mA / hour provides a 10 hours lighting light levels 50 lumens to 60 lumens. LEDs 20 the light intensity will be from 100 to 120 lumens.

LED powered at 220 Volts

LED only works at low voltages and still need to use a series resistor. Not a good idea to limit the current at higher voltages using a resistance due to the power dissipated will be too high and the resistance will burn.

LDR switch circuit diagrams

LDR switch circuit diagrams

It is a light switch or light activated relay circuit. Relay when uncovers LDR and relay when covered. Adjust VR1 for light sensitive. LED is lit simultaneously with the relay.

Light Operated Relay Circuit Schematic

Light Operated Relay Circuit Schematic

LDR is used as the light sensor. Low resistance of about 100 ohms in bright light, but increases to 10 megs or more in the dark. Pre-set VR1 sensitivity LDR. LDR will perform during the day so that you will not get T1 gate bias on the base. Therefore, the relay remains deactivated. When the light intensity is reduced, LDR provides more resistance and more current passes to the base of T1 and is being carried out. Then switch to the deportation of pregnancy. Adjusting VR1 to move the relay, especially in the light level. LED indicates the relay activation

LDR Circuit Diagram

This LDR circuit diagram shows how you can make a detector of light / dark .

LDR circuit diagram

An LDR or " Light Dependent Resistor " is a resistor where the resistance decreases with the strength of the light.


How The LDR Circuit Diagram Works
The circuit diagram of LDR works:

When there is light , the LDR has low resistance. So the voltage at the base of the transistor is not high enough to turn the transistor on .

Therefore, no current will go from the collector to the emitter of the transistor . All current instead pass through the potentiometer and LDR .

Clap Switch

Here's a Hobby Circuit for electronics hobbyists that can change on and off a light, Fan, Radio, etc by the sound of applause. The sound of applause is received by a small microphone that is shown biased by resistor R1 in the circuit. The microphone changes sound waves to electrical waves is further amplified by Q1. The transistor Q1 is used as a common emitter circuit to amplify weak signals received by the microphone. Amplified output from the collector of transistor Q1 is then fed to the flip-flop multivibrator aka flip- flop circuit.