Dark Sensor
Dark sensor using 2 transistor BC547 When light falls on LDR, its low resistance drives the transistor T1 into conduction. This keeps transistor T2 cut-off due to low base bias. The LED does not get power as long as ambient light…
A home to software testing, electronics circuits & projects, tips and tricks and digital diary.
A home to software testing, electronics circuits & projects, tips and tricks and digital diary.
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Electrical Appliance Protection
This simple circuit of electrical appliance protection is to protect your electrical appliance during irregular power supply. Normally when power goes off we forget switching off our appliances. Especially in India where power cuts are very frequent we tend to leave…
IP Switching and Load Testing
IP Switching in Load testing The most common use for IP Switching is when load testing against a load balancer. Load balancer typically use the IP address to route requests to a particular Web server in the farm. So if…
Fundamentals of Testing – Testing Principles
Fundamentals of Testing – Testing principles Principal 1: Testing shows presence of defects Testing can show that defects are present, but cannot prove that there are no defects. Testing reduces the probability of undiscovered defects remaining in the software but,…
LED Flasher using NE555
LED Flasher circuit using NE555 timer IC R1, R2, C1 and the supply voltage determine the flash rate. For a variable flash rate, replace R1 with a 1 MΩ pot in series with a 22k resistor. The purpose of R3…
USB Reading Lamp
USB reading lamp is powered using USB port. The USB port provide 5 v and 100mA which is sufficient for this circuit. Cut the one end of the USB cable and use RED(pin1) and Black(pin4) for 5v positive and negative…
Basic Electronics – Resistor Combinations
RESISTOR COMBINATIONS When we do not get specific resistor values we have to either use variable resistors such as potentiometers or presets to obtain such precise values. Pots are too expensive to use forevery case. Another scheme is to combine…
10 Stage LED Sequencer
10 Stage LED Sequencer Components IC1- CD4017 IC2- NE555 C1 – 1μ C2- 0.01 μ R1 – 470 Ω R2 – 100 KΩ R3- 100 Ω LED1-10 – RED LED 9volt DC power supply. …
Variable DC Power Supply using LM317
Below is the circuit for variable dc power supply R1- 240 Ω R2- 5K VR R2 can be replaced by fixed value resistor for fixed power supply. Following formula can be used to calculate output voltage. Vo=1.25(1+R2/R1) Output voltage should be2…
20 Watt Inverter
This circuit will drive a 40 watt fluorescent or two 20-watt tubes in series. The transformer is wound on a ferrite rod 10mm dia and 8cm long. The wire diameters is 0.61mm wire for the primary and 0.28mm wire for…