The schematic shown below measures capacitance from 2.2pF to 1000pF in the L (low) range, and from 1000pF to 2.2uF in the H (high) range. ICD of the 74HC132 (pin 11) produces a 300 Hz square-wave clock. On the rising edge CX rapidly charges through D1. On the falling edge CX slowly discharges through R5 [...]

This is an simple and cheap circuit to convert voltage from 12V to 3V.In fact this is a basic regulator circuit.The output voltage determined by Vout = Vzener – Vbe When Vzener is zener voltage output. Vbe is saturate voltage when transistor on (about 0.6V)

R1-15-16-21-22-17-18=1Kohm R33=68ohm 5W Q1-2=BC550C R2=47Kohm R35-36=6.8ohm 1W Q3-4=BC560C R3-4=10Mohm TR1=1Kohm trimmer Q5=BC560C R5-6-13-14=1.2Kohm TR2=1Mohm trimmer Q6=BC550C R7-12=47ohm C1=2.2uF 63-100V MKT Q7-11=BD140 R8-9-10-11=22ohm C2=1nF 100V MKT Q8-9-10=BD139 R19=82ohm C3-4=2.7nF 100V MKT Q12=IRF9540 R20=22Kohm C5=330pF Q13=IRF540 R23-26=56ohm C6-7=100uF 16V F1-2=Fuse 2.5A Fast R24=2.2Kohm C8=1uF 100V MKT L1=see text R25=560ohm C9-11-12=100nF 100V MKT J1= 2pin connector 2.54mm step [...]

Download complet project – ESR meter in pdf format

Parts: Ic1 – 78L05 T1,T3 – bc547 npn T2,T4 – bc557 pnp D1,D2 – 1n4148 D3 – zener 13v D4 – zener 12v D5,D6 – zener 5v1 R1 – 1k2 R10- 270 R15- 1k R7,R8 – 10k R4,R5,R13,R14 – 1k8 R2,R3,R6,R9,R11,R12-5k6 c1,c2,c3 – 100nF c4-10uF/16v c5-100uF/25v Led1 – red 5mm led Led2 – green 5mm [...]

Parts: R1 = 1K C1 = 1uF/35V R2 = 3,3K C2 = 470pF R3 = 100 C3 = 100uF/60V R4 = 330 C4 = 100uF/60V R5 = 3,3K C5 = 10uF/60V R6 = 1K C6 = 47uF/60V R7 = 0,33 C7 = 8,2pF R8 = 33? C8 = 0,1uF R9 = 4,7 C9 = 1uF/35V [...]

C1 ——-1 0.0047uf Mono Capacitor C2 ——-1 0.1uf Disc Capacitor D1, D2 —2 1N4007 Diode FTB —–1 Filtered Blacklight Tube IC1 ——1 555 Timer IC P1 ——-1 10k Trim Pot Q1 ——-1 TIP30 PNP Power Transistor R1 ——-1 470 Ohm Resistor R2 ——-1 270 Ohm Resistor T1 ——-1 Medium Yellow Inverter Transformer MISC —-1 IC [...]

General Description This is a small but quite powerful FM transmitter having three RF stages incorporating an audio preamplifier for better modulation. t has an output power of 4 Watts and works off 12-18 VDC which makes it easily portable. It is the ideal project for the beginner who wishes to get started in the [...]

This is circuit Regulator 5V 3A by IC LA5105. (easy circuit) To use transformer 4A. IC to Hold Heatsink. For Digital circuit.

This is a simple XTal tester circuit. T1 and XTal have formed an oscillator. C1 and C2 are voltage divider for oscillator. if the XTal is safe, the oscillator will work well and its output voltage will be rectified by C3, C4, D1 and D2, then T2 will run and LED will light. The circuit [...]