Door Knob Touch Alarm
This is door knob touch alarm for your home security purpose. The alarm will be activated when someone touch the metal door knob. This circuit won’t work on full metal door.
Search Results for: variable resistor
Mini FM Transmitter
This is a mini fm transmitter circuit. I think this is the simplest one. Simple, easy and of course… inexpensive… The supply voltage is between 1.1 – 3 Volts with power consumption is 1.8 mA at 1.5 Volts. This circuit should be able to cover 30 – 50 meters of range max. at 1.5 Volts.… Read More »
Electronic Buzzer with IC timer NE555
This easy electronic buzzer circuit built based on timer works for gaining the frequency. The IC timer NE 555 used as astable multivibrator operating at about 1kHz and produces a sound when switched on. The sound frequency can be adjusted by varying the 10K resistor. You may change the 10K resistor with variable resistor.
Ultrasonic Sensor Switch
Here is the circuit diagram of ultrasonic sensor switch. There are many methods of wireless switching such as by using infrared, AM/FM signal, bluetooth, etc. This is an alternate wireless switching by using ultrasonic sensor. The distance of switching range should be more than 10 meters. This circuit produces and transmits ultrasonic sound of frequency… Read More »
100 Watt Inverter 12VDC to 220VAC with Mosfet
This is another 100 watt inverter circuit diagram. Built based on IC CD4047 and Mosfet IRF540, this inverter have ability to supply electronic device -which require 220VAC- up to 100w from 2-3A transformer from 12V lead acid battery. In the circuit diagram we can observe that 12V battery is connecter to the diode LED and… Read More »
Analog Flip-Flop
Here the analog flip-flop circuit which built based on 2 transistors work as switch. This is very easy made and very cheap circuit. You can use this circuit as “the first project” for your students… 🙂 and the result should be like this:
DC Motor Controller Project Kit
DC Motor Controller Project Kit There are three ways to vary the speed of DC motors: Use a gear-box. Use a series resistor. Measure the current drawn by the motor and then calculate the value of a series resistor needed to drop the voltage applied to the motor. Less voltage means the motor will slow… Read More »
12V 4A Solar Photovoltaic Battery Charger
This is the circuit diagram of 12 Volts, 4 Amperes Solar Photovoltaic (PV) battery charger which will be suit to charge a 12V battery or accumulator. The circuit handles up to 4 amps of current from a solar panel, which equates to about 75 watts of power. A charging algorithm called “pulse time modulation” is… Read More »
Light Fence with LDR
This is the light fence schematic diagram uses LDR as the light sensing. The fundamental issue with the greater part of standard light sensors is that they require exact arrangement of light bar to quiet the circuit throughout standby mode. The circuit portrayed here is sensitive to the point that it will catch a moving… Read More »