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For car alarms, emphasis should be put on hearing the audible alert and identifying it as belonging to your 'wheels'. Unfortunately, modern car alarm systems seem to have more or less the same alarm sound especially if they are from the same brand. Also, to comply with legal noise restrictions, the alarm sound is not always loud enough to be heard if the car is parked down the road. Circuit diagram : Simple Car Alarm Sound Booster Circuit Diagram The circuit shown here is designed to help boost the alarm sound by also activating the car's horn(s) when the alarm goes off. lnternally the car alarm system often provides a signal that activates the (optional) engine immobilizer and/or volume (ultrasound) sensors. This signal usually goes Low upon sys-tem triggering and high again when the alarm system is deactivated. The alarm activation signal is fed to the circuit through Dl . When in idle state, T1 's gate is High and consequently the FET conducts,  keeping  power ...

The USB serial bus can be configured for connecting several peripheral devices to a single PC. It is more complex than RS232, but faster and simpler for PC expansion.Since a PC can supply only a limited power to the external devices connected through its USB port, when too many devices are connected simultaneously, there is a possibility of power shortage. Therefore an external power source has to be added to power the external devices. USB Power Booster Circuit Diagram In USB, two different types of connectors are used: type A and type  B. The circuit presented here is an add-on unit, designed to add more power to a USB supply line (type-A). When power signal from the PC (+5V) is received through socket A, LED1 glows, opto-diac IC1 conducts and TRIAC1 is triggered, resulting in availability of mains supply from the primary of transformer X1. Now transformer X1 delivers 12V at its secondary, which is rectified by a bridge rectifier comprising diodes D1 through D4 and filtered by c...

The USB serial bus can be configured for connecting several peripheral devices to a single PC. It is more complex than RS232, but faster and simpler for PC expansion.Since a PC can supply only a limited power to the external devices connected through its USB port, when too many devices are connected simultaneously, there is a possibility of power shortage. Therefore an external power source has to be added to power the external devices. Circuit diagram: USB Power Booster Circuit Diagram In USB, two different types of connectors are used: type A and type  B. The circuit presented here is an add-on unit, designed to add more power to a USB supply line (type-A). When power signal from the PC (+5V) is received through socket A, LED1 glows, opto-diac IC1 conducts and TRIAC1 is triggered, resulting in availability of mains supply from the primary of transformer X1. Now transformer X1 delivers 12V at its secondary, which is rectified by a bridge rectifier comprising diodes D1 through D4 ...

Volt regulators such as the LM708, and LM317 series (and others) sometimes need to provide a little bit more current then they actually can handle. If that is the case, this little circuit can help out. A power transistor such as the 2N3772 or similar can be used. The power transistor is used to boost the extra needed current above the maximum allowable current provided via the regulator. Current up to 1500mA(1.5amp) will flow through the regulator, anything above that makes the regulator conduct and adding the extra needed current to the output load. It is no problem stacking power transistors for even more current. (see diagram). Both regulator and power transistor must be mounted on an adequate heatsink. Circuit diagram: Ampere or Current Booster Circuit Diagram Parts: R1 = 1R-2W R2 = 10R-2W C1 = 35v-470uF C2 = 35v-470uF Q1 = TIP2955 IC1 = 78xx Regulator

The following couple of circuit diagrams provide a glimpse of the configuration for making a precision rectifier and direct coupled power source circuits.  Precission Rectifier circuit diagram. Direct Coupled Power Circuit Diagram CMOS Power Booster Circuit Diagram The MC1556 operational amplifier way be used as a voltage follower ln a hid; amplifier application. The high input impedance avoids loading effects on the bridge and transforms the impedance down to a level where a third amplifier used in a differential mode can provide voltage gain, ll) in this case. The third amplifier employs the standard offset adjust circuit to provide nulling capability for the configuration. Although the circuit is shown for complementary supply voltages, , it lends itself well to operation from a single supply since the bridge can be operated iust as well from the single supply. One must, however,,provide for biasing the nowgrounded 100 kS2 resistor to half the supply voltage using a simple resis...

MP3 players are all the rage these days. The smaller ones in memory-stick format are particularly easy to take with you; your very own ‘personal sound system’ on the move! It’s when you want others to share your taste in music that you find these players to have a lack of power. You can get round this problem with the help of the MP3 booster, a small amplifier that can be used to connect your MP3 player directly to your Hi-Fi. When you next invite your friends to a party you can ask them to bring their ‘personal music’ as well as the usual drinks! But first we have to build this booster! The small battery-powered players have an output signal that is more than sufficient to drive a set of 32 Ohm headphones. You’ll often find that with an output of 1mW the sound pressure level (SPL) produced can reach up to 90 dB. This would be sufficient to cause permanent damage to your hearing after only one hour! The maximum output voltage will then be around 200mV. This, however, is insufficient to fully...