Converter Circuits

DRM Down-Converter For 455kHz IF Receivers

This project came about due to my interest in a new form of radio transmission called DRM, which stands for “Digital Radio Mondiale” (see This is a new form of digital shortwave transmission. A few devices are available from Europe for decoding the digital signals but are expensive. I decided instead to modify an […]

12V to 250V Converter

A very simple portable 12 to 250V converter can be designed using this circuit diagram. This 12 to 250V converter is designed for portable use with a 12 V car battery.A built astabil multivibrator T1 and T2 generates a rectangular wave at a frequency of 50 Hz. As T1 and T2 drive alternative exit stage […]

Balanced-Unbalanced Converter For Audio Work

If you work in the professional audio field, you need to use balanced lines for long signal runs to prevent hum and noise pick-up. This Balanced/Unbalanced Converter is really two projects in one. It can convert an unbalanced input to balanced outputs and vice versa. Specifications: Signal to noise ratio: -100dB with respect to 1V […]

12V From USB Port – 5V to 12V Converter

Using this circuit we can convert 5V DC from the computer USB port to 12V DC and a circuit like this will find a lot of application in USB powered systems. The heart of this circuit is IC LT1618 which is a constant current, constant voltage boost converter. The IC has a wide input voltage […]

Buck-Boost Voltage Converter

Sometimes it is desired to power a circuit from a battery where the required supply voltage lies within the discharge curve of the battery. If the battery is new, the circuit receives a higher voltage than required, whereas if the battery is towards the end of its life, the voltage will not be high enough. […]

12V to 9V DC Converter

To get a more precise output voltage, replace zener diode Z1 with 10V and R1 with a 1Kilo ohm potentiometer. A Coolrib for Q1 is optional but highly recommended. You can replace Q1 for a more robust type to get more output amps depending on your requirements. Simple circuit to power your 9 volt cassette […]

Cheap Switch-Mode DC-DC Converter

This circuit is based on mobile phone chargers. These chargers are based on the Motorola MC34063 switchmode IC. By changing the values of the feedback resistors (R1 & R2), the output voltage can be varied over a wide range. Just modify R1 and R2 according to the formula: Vout = 1.25 (1+R2/R1). The values shown […]

DC/DC Converter From +1.5V To +34V

An interesting DC/DC converter IC is available from Linear Technology. The LT1615 step-up switching voltage regulator can generate an output voltage of up to +34V from a +1.2 to +15V supply, using only a few external components. The tiny 5-pin SOT23 package makes for very compact construction. This IC can for example be used to […]

RMS to DC Converter

In order to measure the RMS value of an alternating voltage an accurate converter is required to produce the true RMS value of its alternating input as a DC output. With simple sinewave inputs the RMS voltage can simply be calculated as 0.707 times the peak AC voltage, but with complex waveforms the calculation is […]

Sine Wave To TTL Converter

As the title implies, the present circuit is intended to convert sinusoidal input signals to TTL output signals. It can handle inputs of more than 100 mV and is suitable for use at frequencies up to about 80 MHz. Transistor T1, configured in a common-emitter circuit, is biased by voltage divider R3–R5 such that the […]