Electronic Circuits Schematics Projects




AC to DC & DC to DC


Bipolar power supply for battery instruments

To generate regulated ± 5-V supplies from a pair of dry batteries, the circuit of Fig. 1 is commonly used. In order to give protection from inadvertent reverse connection of a battery, a diode in series with each battery would produce an unacceptable voltage drop. The more effective approach is to fit diodes Dl and D2 as shown in Fig. 2, in parallel with each battery. When the supply is switched off, there is the risk of a reverse bias being applied across the.....


Views: 2448 | Votes: 101 | Comments: 0 | Rating: 2 | Rank: 6 | Added: Apr 1, 2013 |
Diode Cmos Stabilizer

The simple diode network can stabilize the voltage supplied to CMOS circuitry from a battery. D1 and D2 must have a c..


Views: 10 | Votes: 6 | Comments: 0 | Rating: 5 | Rank: 5 | Added: Mar 31, 2013 |
Regulator Loss Cutter Circuit

Large input-to-output voltage differentials, caused by wide input voltage variations, reduce a linear regulator`s efficiency and increase its power dissipation. A switching preregulator can reduce this power dissipation by minimizing the voltage drop across an adjustable linear regulator to a constant 1.5-V value. The circuit operates the LT1084 at slightly above its dropout voltage. To minimize power dissipation, a low-dropout linear regulator was chosen. The LT1084.....


Views: 10 | Votes: 56 | Comments: 0 | Rating: 3 | Rank: 5 | Added: Mar 19, 2013 |
Power pack for battery-powered devices

This circuit gives a regulated output of between 5 V and 15 Vdc, adjusted and set by a preset resistor. Current output up to about 350 mA..


Views: 911 | Votes: 86 | Comments: 0 | Rating: 9 | Rank: 5 | Added: Mar 17, 2013 |
Low voltage regulators

These short-circuit protected regulators give 6, 7, and 9 V from an automobile battery supply of 13 V nominal; however, they will function just as well if connected to a smoothed dc output from a transformer/rectifier circuit. Two types are shown for both positive and negative ground systems. The power transistors can be mounted on the heatsink without a mica insulating spacer thus allowing for greater cooling efficiency. Both circuits are protected against overload or.....


Views: 1745 | Votes: 107 | Comments: 0 | Rating: 7 | Rank: 5 | Added: Mar 16, 2013 |
General-purpose-power-supply

The supply 6-66 can be used for supply output voltages from 1 to 35 V. The line transformer should be selected to give about1.4 times the desired output voltage from the positive side of filter capacitor C1 to ground. Potentiometer R2 sets the output voltage to the desired value by adjusting the reference input. Rsc is the current limit set resistor. ..


Views: 26 | Votes: 5 | Comments: 0 | Rating: 8 | Rank: 5 | Added: Mar 16, 2013 |
Three-rail-power-supply

This circuit generates three supply voltages using a minimum of components. Diodes D2 and D3 perform full-wave rectification, alternately charging capacitor C2 on both halves of the ac cycle. On the other hand, diode D1 with capacitor C1, and diode D4 with capacitor C3 each perform half-wave rectification. The full-and half-wave rectification arrangement is satisfactory for modest supply currents drawn from -5 and +12-V regulators IC3 and IC2. ..


Views: 7 | Votes: 56 | Comments: 0 | Rating: 2 | Rank: 5 | Added: Mar 16, 2013 |
Diodeless Rectifier Circuit

It`s common knowledge that when working with single-supply op amps, implementing simple functions in a bipolar signal environment can be difficult. Sometimes additional op amps and other electronic components are required. Taking that into consideration, can any advantage be attained from this mode The answer lies in this simple circuit (A). Requiring no diodes, the circuit is a high-precision full-wave rectifier with a liigli-frequency limitation equalling that of the op.....


Views: 10 | Votes: 7 | Comments: 0 | Rating: 1 | Rank: 5 | Added: Mar 15, 2013 |
0-30 Volts / 2,5A Variable Power Supply

This is a high quality power supply with a continuously variable stabilized output adjustable between 0 and 30VDC. the LM 723 is the heart of the power supply which drives the BD137 and then the 2N3055. The circuit provides short circuit protection. And has great stability at voltage changes. ..


Views: 3763 | Votes: 64 | Comments: 5 | Rating: 7 | Rank: 10 | Added: Mar 11, 2013 |
12-16V-converter

Many devices operate from a car"s 12-V electrical system. Some require 12 V; others require some lesser voltage. An automobile battery"s output can vary from 12 to 13.8 V under normal circumstances. The load requirements of the device might vary. This circuit maintains a constant voltage regardless of how those factors change. Simple circuit, A, uses a 7805 voltage regulator. ..


Views: 13 | Votes: 100 | Comments: 0 | Rating: 3 | Rank: 5 | Added: Mar 11, 2013 |
Up-Controlled Negative Voltage Converter

This circuit was used to produce a variable negative voltage for contrast control of an LCD displa..


Views: 0 | Votes: 31 | Comments: 0 | Rating: 9 | Rank: 5 | Added: Mar 11, 2013 |
0 To 12V, 1A Variable Power Supply Circuit

This 0- to 12-Vdc variable power supply uses an IC voltage regulator and a heavy-duty transformer to provide a reliable dc power supply. Looking at the schematic shown, you can sec that transformer Tl has a 120-V primary and a 28-V secondary. Filtered dc is fed to the input (pin 2) of the LM317T voltage regulator, IC, which keeps the voltage at its output constant (pin 3) regardless (within limitations) of the input voltage...


Views: 19 | Votes: 75 | Comments: 0 | Rating: 5 | Rank: 5 | Added: Mar 9, 2013 |
Antique Radio Dc Filament Supply Circuit

This dc supply is great for operating battery-powered antique radios, because it is designed to prevent harming the tube filaments. ..


Views: 5 | Votes: 104 | Comments: 0 | Rating: 3 | Rank: 5 | Added: Mar 6, 2013 |
Overvoltage protection for logic

Zener diode ZD1 senses the supply, and should the supply rise above 6 V, Ql will turn on. In turn, Q2 conducts clamping the rail. Subsequent events depend on the source supply. It will either shut down, go into current limit or blow its supply fuse. None of these will damage the TTL chips..


Views: 70 | Votes: 21 | Comments: 0 | Rating: 6 | Rank: 5 | Added: Mar 5, 2013 |
8V From 5V Regulator Circuit

If you have trouble locating an 8-V regulator, although they are commonly available,..


Views: 0 | Votes: 32 | Comments: 0 | Rating: 9 | Rank: 5 | Added: Mar 5, 2013 |
Basic single-supply voltage regulator

The circuit uses a CA3140 BiMOS op amp capable of supplying a regulated output that can be adjusted from essentially 0 to 24 volts. ..


Views: 4414 | Votes: 3 | Comments: 0 | Rating: 4 | Rank: 4 | Added: Mar 2, 2013 |
Hand-held-transceiver-dc-adapter

This de adapter provides a regulated 9-V source for operating a Kenwood TR-2500 hand-held transceiver in the car. The LM317T"s mounting tab is electrically connected to its output pin, so take this into account as you construct your version of the adapter. ..


Views: 4 | Votes: 60 | Comments: 0 | Rating: 8 | Rank: 5 | Added: Feb 23, 2013 |
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..


Views: 4 | Votes: 5 | Comments: 0 | Rating: 0 | Rank: 5 | Added: Feb 23, 2013 |
Tracking Double-Output Bipolar Supply Circuit

This circuit is useful for a bench supply in the lab. Separate or tracking operation is possible. The regulators should be properly heatsinked...


Views: 9 | Votes: 57 | Comments: 0 | Rating: 8 | Rank: 5 | Added: Feb 23, 2013 |
13.8Vdc 2A Regulated Power Supply Circuit

This regulated power supply consists of step-down transformer Tl, a full-wave rectifier bridge (D1 through D4), and a filtering regulator circuit made up of Cl, C2, Rl, R2, R8, D5, and Ql, When 120 Vac is provided, the neon-lamp assembly LI lights up, and transformer Tl changes 120 Vac to about 28 Vac. The rectifier bridge, )1 through D4, rectifies the ac into pulsating dc, which is then filtered by Cl. Capacitor Cl acts as a storage capacitor...


Views: 12 | Votes: 13 | Comments: 0 | Rating: 5 | Rank: 5 | Added: Feb 19, 2013 |