If you’re interested in RF circuit, then you should know about this basic RF oscillator. This basic RF oscillator circuit is easy to build and the components are not critical. Most of them can be found in your junk parts box. The circuit operated with 9VDC power supply. The L1 antenna col can be made… Read More »
Here the SW transmitter circuit based on IC BEL1895. This particular transmitter circuit works in shortwave HF band (6 MHz to 15 MHz), and can be applied for shortrange communication and for educational purposes. The circuit is composed of a mic amplifier circuit, a variable frequency oscillator, and modulation amplifier stages. Transistor T1 (BF195) is… Read More »
This is a simple audio pre-amplifier circuit using single transistor 2N3904. This easy circuit provides good gain to weak audio signals such as electret microphone. Use it in front of an RF oscillator to make an RF transmitter that’s very sensitive to sound. Power supply used for this circuit is wide range from 3VDC to… Read More »
This is the simple and low cost AM transmitter schematic diagram built using transistor BC109C. The circuit is in two halfs, an audio amplifier and an RF oscillator. The oscillator is built around Q1 and associated components. The tank circuit L1 and VC1 is tunable from about 500kHz to 1600KHz. These components can be used… Read More »
This is the circuit design of unipolar stepper motor driver to control unipolar stepper motors with 5, 6 or 8 wires. It uses four MOSFET IRFZ44. This circuit can be operated in free-standing or PC-controlled mode.
This is a low cost, simple, yet a surprisingly powerful electronic siren powered by just a 9V battery. The circuit may provide the final circuit block module in an alarm circuit using a relay to activate it.
This is the simple and low cost pulse width modulation – PWM DC motor controller using a MOSFET. This kind connection for DC motor control is to prevent heat and minimize the power consumption. It controls the motor speed by driving the motor with short pulses. These pulses vary in duration to change the speed… Read More »
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 »
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 multi-element Yagi antenna or 50-ohm ground—plane antenna, this transmitter can give great good signal strength up to a distance… Read More »