Today, surfing the Internet and found another on the meter replacement circuit 9V supply, and now extract as a reference, it can be said that I saw the simplest circuit, and we can try. VGP-BPS9/S VGP-BPS8A
Always felt that replacing the circuit very well, because the battery is not sustainable, because the multimeter, many from the walking tour, but since the bifurcation need to compare a lot of time to stop, so wait free time, consume much energy the battery is not sustainable. Before I had a circuit using 1.5V battery, there are good times we forget to turn off, wasting a lot of energy, the battery is very durable, no electricity per month, so in exchange ‘9V laminated battery is even better.
The Party of origin as follows:
1. Circuit works
Alternative multimeter power supply circuit in Figure 1. Circuit consists of transistor VT, step-up transformer T, the diode VD, a capacitor C and GB be composed of five elements. Transistor VT and step-up transformer T is a feedback oscillator transformer when the output power to the load current is exceeded, the transistor base current VT adopted, the oscillation circuit on work, on the contrary, he n ‘there is no current basis, the current consumption of the battery is not therefore the circuit without power switch.
2. Selection of components and installation and implementation IBM ThinkPad R40 battery IBM ThinkPad X60 battery
VT-type PNP low power transistor, such as 2N3906, β> 200.
VD: 1N4148-type diode switching.
C: 1uF/16V.
T: step-up transformer, using Φ10mm magnetic ring as a framework, the primary winding L2 Φ0.15mm enameled wire around the 16 laps, the sub-L1 with Φ0.08mm son enamelled winding around the 140 laps. Around the system before using the plates of plastic or bamboo is a small shuttle. Cut each end of a small crossings, the enameled wire around the shuttle, then re-winding.
Multimeter offers alternative supply printed circuit of Figure 3. Power PCB according to the size of icons with Daoke legislate, not perforated, all components can be soldered directly on the Dell Latitude D500 battery Dell Latitude D520 battery copper surface. The battery installed on the circuit, its positive and negative effects on the P-Cu film with the flexibility to make a clamp, welding the corresponding position in the printing plate fixation. Shell with the size of the battery cell is similar, but can also be directly installed in the meter box.
The circuit is completed and fully verifies the correct welding, you can debug electricity. Firstly, the output terminal connected to a voltage of 3 kΩ/0.125W resistance, the dc voltage with range multimeter measures