Here the cheap hearing aid to help people who have hearing loss. Commercially available assistive hearing devices are quite expensive. This is a cheap hearing aid device circuit which works by using just four transistors and several passive electronic components.
This is the schematic diagram of DC motor speed controller circuit. The circuit applies two oscillators/timers which are connected as a Pulse Width Modulator (PWM). The timer chip which applied in this circuit will be an nmos dual timer/oscillator NE556. This timer IC has two 555 timers in a single 14-pin IC package.
Here the simple schematic of multitone siren alarm circuit. This multitone siren is effective for reverse horns, burlgar alarms, and many others. It generates five various audio tones and is much more earcatching than a single-tone siren.
This is the circuit diagram of stereo tube amplifier using 6SQ7-GT and 6V6-GT. The tube amplifier circuit is uses the total of 5 power vacuum tube. The diagram is based on the output section design of typical late 1940’s old AM Trutone radio with 6 tubes. The output will be 4 Watts per channel (2x4W… Read More »
This is a low cost and easy build low powered FM transmitter. The range of the FM transmitter claimed about 300 feets when running at 9V supply. And the range claimed to be increased become about 400 feet when running it at 12V supply. Take a note that this transmitter should not be used as… Read More »
This is a very easy build, simple metal detector circuit, built based on a CS209A IC. The circuit will give surprising results and draws extremely small current from a 9 volt battery. It worked great on the bench, but not so good outside for common metal detecting. But definately a great circuit for sensing studs… Read More »
The following circuit is a simple, cheap and easy build motorcycle alarm. The circuit just required 2 transistors to drive the relay the the relay act as a switch to activate the buzzer. Any number of normally-open switches may possibly be applied. Fit the mercury switches to ensure that they close when the steering is… Read More »
The following diagram is a very easy and simple electronic combination lock based on IC LS7220. Component Part List: C1 = 1uF 25V C2 = 220uF 25V R1 = 2.2K Ohm Q1 = 2N3904 / 2N2222 D1 = 1N4148 / 1N4001-1N4007 K1 = 12V SPDT Relay / Any appropriate relay with 12V coil U1 =… Read More »
This is an 250mW RF power amplifier circuit project. This circuit is designed to amplify the output of about 7mW wide band FM transmitters to a final level of about 250mW. General purpose 12V DC power supply can be used to operate this RF amplifier circuit. Schematic Diagram: Components List: R1 ____________________ 10R R2 ____________________… Read More »