This battery charger automatically starts the charging procedure when battery voltage drops below a certain predefined value and stops after the voltage has risen above the maximum allowed value. Setup can’t be easier, just connect two alligator clips to battery terminals and plug the device in mains. This way it can stay connected for months [...]
This cheap and easy to build NiCd/NiMH Battery Charger is suitable for automatically charging a wide range of batteries for many applications. Proper chargers are usually expensive and cheap chargers supplied with the original equipment often incorrectly charge the cells and dramatically shorten their life. This ‘intelligent’ charger was designed for high current and rapid [...]
This is a automatic battery charger, after completing the charge it turns off automatically. It runs on AC power but you can also run it with DC power. Its not my idea or my invention, I got it from net. After understanding the circuit I built it and it works fine. So try to built [...]
Lithium-Ion cells require a constant voltage, current limited charge. The voltage must be accurately limited to 4.2V, as higher voltage reduces cell life. This circuit is designed to meet these requirements using standard components.
Source: bhabbott
The circuit consists of two parts, a constant current generator using a PNP power transistor (Q2), and a peak-detecting shutoff circuit using a high-gain opamp (IC1). To start the charge cycle, switch SW1 is momentarily closed, causing C1 to discharge. As IC1’s inverting input is now higher than its non-inverting input, its output goes low, [...]
Most off-the-shelf car battery chargers cannot not be left connected to the battery for long periods of time as over-charging and consequent battery damage will occur. This add-on circuit is placed in series with the battery being charged and is powered by the battery itself.
In effect, the circuit uses a high-current Mosfet to control the [...]
Portable iPod charger that you can use while away from your computer. The circuit is based around an MC34063 switchmode regulator. This has high efficiency so that there is very little heat produced inside the box, even when delivering its maximum output current. The circuit is more complicated than if we used a 7805 3-terminal [...]
Parts:R1 33 ohm D1 1N4007R2 10 kohm U1 B250C1000RR3, R8 5,6 kohm T1, T2, T3 BC548BR4, R7 100 kohm ZD 6,8 V, Zener.R5 2,7 Mohm LED1 ?ervená / [...]
Build-in charger for instruments powered single Li-ion or Li-pol accumulator. If external charge voltage not conected to charger, back current from accu to charger is very small (not measured ordinary multimeters)
This project allows instant start sequentially but a dozen low-voltage lamps 12 V / 60 W, and makes them fade and always sequentially (but slower). This system has been designed to meet the demand of a visitor who wanted ten recessed low voltage spot in a driveway to his house, with the following function: – [...]
This circuit allows switching on a LED when the battery voltage (12V) drops below a certain threshold. The operating system is based on a comparison of tension, which comes in a zener diode. If the supply voltage is 12V and the zener diode is a 10V model (this is the case in the diagram), we [...]
This is a good looking and practical device that can be useful in many areas where countdown timer is needed. This project is based on the PIC16F84A microcontroller. The time range can be adjusted between 1 and 999 seconds. This project has 3 buttons and one of them is named Set Button. In order to [...]
A VU meter is often included in audio equipment to display a signal level in Volume Units; the device is sometimes also called volume indicator (VI). In this project we are building a basic and low cost LED VU Metre circuit . The extent (range) display is -18 dBu to +3 dBu, spread over [...]
Today we have a new category “Projects” and a new electronic project 12 Channel LED Chaser with PIC16F84A.
This project is based on the popular PIC16f84A micro-controller.The heart of this project LED chaser is the PIC16F84A PIC microcontroller.A 4MHz crystal and capacitors C1 and C2 22pf is used for providing clock pulses to the micro-controller. The [...]
