Here the simple and low cost FM transmitter circuit. The frequency range of this FM transmitter should be about 89MHz – 109MHz. Output power is about 9mW at 9V. Components List: Resistors: R1, R6 : 12K R2, R4 : 100K R3 : 22K R5 : 1K R7 : 100R Capacitors: C1 : 10uF/25V C2 :… Read More »
This a two station intercom. It uses two wires to run between each intercom unit. Each is self contained with its own battery, speaker, microphone and amplifier circuit. An LM386 audio power amplifier is used. It is widely available, used a minimum of external parts and is well suited to battery operation. It will give… Read More »
Here the circuit diagram of 25 watt Hi-Fi (high fidelity) audio amplifier that build based on single power amplifier IC LM1875 that should be run using heatsink attached on its. Components List: R1 _____________ 1K R2 _____________ 1M R3 _____________ 22K R4 _____________ 10K R5 _____________ 180K R6 _____________ 1R IC1 ____________ LM1875 C1 _____________… 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 dynamic microphone amplifier circuit diagram. This circuit should be perfect for dynamic microphone… Dynamic microphones are versatile and ideal for general-purpose use. They use a simple design with few moving parts. They are relatively sturdy and resilient to rough handling. They are also better suited to handling high volume levels, such as… Read More »
Here the circuit diagram of 22W stereo power amplifier. Powered with main power IC TDA1554Q, this circuit works up to 22W for each channel. For stereo channel, the power output should be up to 2 x 22W . A few externel components required to support the main component. Heatsink on the power IC is a… Read More »
Below is the circuit diagram and PCB layout of FM wireless microphone: The range of frequencies for the FM broadcast band is 90MHz (MHz = Megahertz or 90 million cycles per second). Because the FM microphone has a variable tuned circuit, it can be tuned to a quiet spot on your local FM broadcast band… Read More »
Hobby power supply for electronic hobbysts. This is power supply circuit which have 2 output that are static output and adjustabled output. The static output is stabled and regulated output. The circuit is based around the 7805 voltage regulator. It has only 3 connections (input, output and ground) and it provides a fixed output. The… Read More »