This is a very simple FM receiver which build based on one transistor only. No chip or another active component. The output is connected to earphones, you need an amplifier circuit if you want to listen the radio with a loudspeaker.
This is 0-24VDC digital PIC power supply circuit. This variable power supply controlled with PIC microcontroller. There is LCD display in this circuit which will show the actual value of power supply output. This power supply use push on switch to adjust the output voltage and current value. Schematic Diagram: Component List: C1 = 2000uF… Read More »
This is the circuit of LED color fade effect. Just like the name of the circuit, the light intensity of LEDs in this circuit will fade from high intensity to low intensity and then off. Here the final result preview:
Here the circuit diagram of safer security system alarm. There are many security systems use a closed loop of wires and switches arranged so that whenever a door or window is opened, the loop will be broken and the alarm will sound. An obvious problem is that someone can tamper with the system, short out… Read More »
Here is the circuit diagram of simple multitone alarm. This is a low cost circuit which is simple and easy to build. The main components of this circuit is based on dual op-amp MC1458 and LM 380. The two op amps inside the MC 1458 are used to produce square and triangular waves. LM 380… Read More »
Here is the circuit diagram of active DC voltage doubler which used to increase the DC voltage. This circuit drives relays of 24 and 18VDC from a 12V power supply. Use this circuit can be work with almost any PNP or NPN power transistor, of course the transistor with specific characteristic similar to the transistor… Read More »
This is the circuit diagram of dancing LEDs which consists of 10 units LEDs. The 10 dancing LEDs circuit works like a audio level meter. The LEDs will be dance sequence with the sound level that entering the microphone. Components list: R1_____________10K 1/4W Resistor R2,R3__________47K 1/4W Resistors R4______________1K 1/4W Resistor R5,R6,R7______100K 1/4W Resistors R8____________820R 1/4W… Read More »
Here is the simple and low cost NiCd and NiMH battery charger circuit which can be used for various battery type and size. This battery charger use a regulator IC of LM317. Schematic diagram: The charge will start if a battery is connected between pins JP1-JP4 or JP2-JP4 or JP3-JP4. For example, if a battery… Read More »