This is a mini FM transmitter built and powered using 2 transistors, designed by Tony van Roon. This small transmitter is simple to build and its transmissions could be picked up on any common FM radio. It possesses a range of approximately 1/4-mile (400 meters) or even more, depending on the line-of-sight, obstructions by big… Read More »
Above circuit diagram is a easy, simple and cheap switching voltage regulator which has capability to deliver adjustable voltage output range of 1.8V to 32V and static electric current of 3A. This regulator use adjustable regulator IC of LM317HV and a power PNP transistor of 2N3792.
The following diagram is the circuit diagram of voice transmitter which use FM signal carrier to transmit the vioce signal to the FM receiver device. Components List: R1 = 4.7K R2 = 330 ohm C1 = 0.001uF (1nF) C2 = 10-40pF C3 = 4.7pF Q1 = 2N3904 L1 = see text Misc = Electret mike,… Read More »
This is the circuit diagram of low forward-drop rectifier. A TMOS power FET (Q1) and a LM393 comparator provide a high-efficiency rectifter circuit. When VA exceeds VB, U1’s output becomes high and Q1 conducts. Conversely, when VB exceeds VA, the comparator output becomes low and Q1 doesn’t conduct.
This is the scheme diagram of automatic 9V battery charger circuit, the parts list provided below the schematic image. The circuit was designed by Jan Hamer, translated by Tony Van Roon dan republished in this circuit diagram site. The circuit details are based on european standards: 120E, 150E, etc. The ‘E’ just stands for Ohms… Read More »
This is the LED pilot light (or LED indicator) circuit. LEDs (Light Emitting Diode) part are interesting things. They only operate at DC supply within specific tolerances, and generally connected with a current limiting resistor towards the power source. Rather than a resistor, it is possible to use a FET (Field Effect Transistor) like the… Read More »
Here is the circuit diagram of lantern dimmer / flasher designed by Tony Van Roon: There are two circuit modes: dimming and flashing. The flasher mode is useful for warning other drivers of your troubles and it may be adjusted to have a very short flash duration for long-term use as when the car must… Read More »
The following is LED Flasher circuit which use 2 transistors for LED switching. The circuit works similar to flip-flop operation. Components List: R1 = 10M ohm R2 = 1K – 100K ohm R3 = 470 ohm C1 = 0.47uF – 10uF/25V D1 = 1N914 Q1 = 2N3904 Q2 = 2N3906 Led = High Brightness Red… Read More »
Designed by Don Tillman, this guitar pre-amp circuit design is dedicated for people who don”t like op-amps module. This circuit is a discrete JFET pre-amplifier design, use 2N5457 as the main component. It has low noise, low distortion, low feedback, overloads gracefully, is small, etc.