This long-range FM radio transmitter has an additional RF power amplifier stage, after the oscillator stage. The extra RF power amplifier used to strenght up the power output to become 200-250 milliwatts. With a great matching […]
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Simple Mat Alarm Switch
This easy to built circuit produces a warning beep when somebody crosses a secure area in your home or place of work. The transfer, hidden beneath the ground mat, causes the alarm whilst the individual walks […]
Variable / Adjustable DC Power Supply 1.2V – 25V using LM338K
This is variable DC power supply circuit, or we can call it adjustable DC power supply which give us a 1.2V-25V output voltage. The power supply schematic above is taken from the datasheet of regulator LM338K […]
Stereo Digital Volume Control
Here is the circuit diagram of stereo digital volume control. This circuit could possibly be applied for upgrading your manual volume management within a stereo amplifier circuit. In this particular circuit, push-to-on switch S1 controls the […]
Simple Mobile Phone Battery Charger
The following diagram is a simple mobile phone battery charger circuit. The design is simple, easy to build and inexpensive. It use LM78xx regulator to make regulated and stable output voltage. Mobile phone chargers offered in […]
Simple Battery Level Indicator
Here the circuit diagram of simple and easy made battery level indicator. In general, in mobile phones, the battery levels is displayed in dot or bar style. This helps you to effortlessly acknowledge the battery level. […]
USB Powered, Stereo Computer Speaker
This is the circuit diagram of USB powered stereo computer speaker, or it widely known as multimedia speakers for PCs. The circuit has single-chipbased design, low-voltage electrical power supply, compatibility with USB power from computer, simple […]
Automatic Switch-Off Staircase Light
This is the circuit diagram of staircase light with automatic switch off. It based on timer which is can be adjusted with the needs of the time of walking (climbing up and going down) on the […]
Portable 230V Lamp Flasher
This is a portable, 230V high-power incandescent electric lamp flasher circuit diagram. It is actually basically a double flasher (alternating blinker) which could manage two different 230V AC loads (bulb lamps L1 and L2). The circuit […]
Electronic Horn
This is an easy, low cost and easy built circuit of an electronic horn which is designed close to quadruple op-amp IC LM3900 (IC1). IC LM3900 has four independent operational-amplifiers (A1 through A4) having a large […]