Fixed Voltage Power Supply

12v to +5V, -12V, +12V, +24V adaptor

Many times we needed a variety of voltages, from a battery 12V. With the circuit, we can take voltages smaller or bigger, positive or negative, from a battery 12V. The idea is based in oscillator roughly 7KHZ, round the R1, C28, that lead the remainder gates of IC1, that are connected at the...

Adjustable 20V Supply Circuit

This circuit, can deliver 3 A or more and a maximum dc voltage ol` a little over 20 V. It is designed around the readily available LM317T adjustable 3-terminal regulator and has a pnp power transistor to boost the current output. The transformer has an 18-V secondary rated at, 6 A; this feeds to...

Precision Full-Wave Ac/Dc Converter

A dc level is produced that corresponds to the ac input rms value (if sine wave), -i set the gain of IC

Bilateral current source

The circuit will produce the current relationship to within 2% using 1% values for Rl through R5. This includes variations in Rl from 100 ohm to 2000 ohm. The use of large resistors for Rl through R4 minimizes the error due to Rl variations

Common Hot-Lead Regulator

This circuit derives 5 Vdc from 2-AA cells—even at their end-life voltages of 1.05 V, and is approximately 80% ef

Supply Voltage Indicator

A novel supply voltage monitor which uses a LED to show the status of a power supply. This simple and slightly odd circuit can clearly show the level of the supply voltage (in a larger device): as long as the indicator has good 12 volts at its input, LED1 gives steady, uninterrupted (for the...

Regulator Combination Circuits

There are a number of ways to obtain the low voltages required to run small projects from the wall power outlet. The simplest way is to buy a factory-built molded supply which is designed to plug directly into the wall outlet. Some such supplies have an internal voltage regulator and need no...

Simple 5V power supply for digital circuits

This circuit is a small +5V power supply, which is useful when experimenting with digital electronics. Small inexpensive wall tranformers with variable output voltage are available from any electronics shop and supermarket. Those transformers are easily available, but usually their voltage...