10 MHz to 1 MHz Converter

This converter circuit convert 10 MHz signal frequency to 1 MHz signal frequency.The 10MHz generated by using crystal 10 MHz and convert to 1MHz by using counter chip 1490A.
Part list :
IC1 = 7404
IC2 = 7490A
R = 1 K
R = 3.3 K
C = 39 pF (Trimmer)
C = 4.7 uF 16V (electrolyte)
C = 47 nF 16 V (Mirra)
C = 10 nF 16 V (Mirra)
C = 68 pF 50 V (Ceramic)

6Vdc to 12Vdc Converter

This converter circuit convert a 6 dc voltage to 12 dc voltage and can provide up to 800mA of 12 voltage power.
Part list :
R1, R4 2 .2K 1/4W Resistor
R2, R3 4.7K 1/4W Resistor
R5 1K 1/4W Resistor
R6 1.5K 1/4W Resistor
R7 33K 1/4W Resistor
R8 10K 1/4W Resistor
C1,C2 0.1uF Ceramic Disc Capacitor
C3 470uF 25V Electrolytic Capcitor
D1 1N914 Diode
D2 1N4004 Diode
D3 12V 400mW Zener Diode
Q1, Q2, Q4 BC547 NPN Transistor
Q3 BD679 NPN Transistor
L1 See Notes
Notes
1. L1 is a custom inductor wound with about 80 turns of 0.5mm magnet wire around a toroidal core with a 40mm outside diameter.
2. Different values of D3 can be used to get different output voltages from about 0.6V to around 30V. Note that at higher voltages the circuit might not perform as well and may not produce as much current. You may also need to use a larger C3 for higher voltages and/or higher currents.
3. You can use a larger value for C3 to provide better filtering.
4. The circuit will require about 2A from the 6V supply to provide the full 800mA at 12V.

12Volt to 9Volt DC Converter

Parts List:
R1 = 560 ohm
C1 = 1000uF/40V, Electrolytic
C2 = 10uF/25V, Electrolytic
C3 = 330nF, Ceramic
Z1 = 9.1V, 1watt zener
Q1 = ECG184, NTE184

Notes:
To get a more precise output voltage, replace zener diode Z1 with 10V and R1 with a 1Kilo ohm potentiometer. A Coolrib for Q1 is optional but highly recommended. You can replace Q1 for a more robust type to get more output amps depending on your requirements. Simple circuit to power your 9 volt cassette recorder and other stuff.

From : http://www.uoguelph.ca/~antoon/circ/car912.htm